15997770 has 64 divisors (see below), whose sum is σ = 43021440. Its totient is φ = 4230144.

The previous prime is 15997769. The next prime is 15997771. The reversal of 15997770 is 7779951.

15997770 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (15997769) and next prime (15997771).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (15997771) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 51957 + ... + 52263.

It is an arithmetic number, because the mean of its divisors is an integer number (672210).

Almost surely, 2^15997770 is an apocalyptic number.

15997770 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 15997770, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21510720).

15997770 is an abundant number, since it is smaller than the sum of its proper divisors (27023670).

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

15997770 is a wasteful number, since it uses less digits than its factorization.

15997770 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 516 (or 510 counting only the distinct ones).

The product of its (nonzero) digits is 138915, while the sum is 45.

The square root of 15997770 is about 3999.7212402866. The cubic root of 15997770 is about 251.9725026686.

The spelling of 15997770 in words is "fifteen million, nine hundred ninety-seven thousand, seven hundred seventy".