69121728 has 224 divisors, whose sum is σ = 232989120. Its totient is φ = 19906560.

The previous prime is 69121709. The next prime is 69121747. The reversal of 69121728 is 82712196.

It is an interprime number because it is at equal distance from previous prime (69121709) and next prime (69121747).

It is a Harshad number since it is a multiple of its sum of digits (36).

Its product of digits (12096) is a multiple of the sum of its prime divisors (216).

It is a junction number, because it is equal to n+sod(n) for n = 69121692 and 69121701.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 381798 + ... + 381978.

It is an arithmetic number, because the mean of its divisors is an integer number (1040130).

Almost surely, 2^69121728 is an apocalyptic number.

69121728 is a gapful number since it is divisible by the number (68) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 69121728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (116494560).

69121728 is an abundant number, since it is smaller than the sum of its proper divisors (163867392).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

69121728 is a wasteful number, since it uses less digits than its factorization.

69121728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 232 (or 216 counting only the distinct ones).

The product of its digits is 12096, while the sum is 36.

The square root of 69121728 is about 8313.9477987296. The cubic root of 69121728 is about 410.3976471258.

It can be divided in two parts, 6912 and 1728, that multiplied together give a square (11943936 = 3456²).

The spelling of 69121728 in words is "sixty-nine million, one hundred twenty-one thousand, seven hundred twenty-eight".