65172780 has 72 divisors (see below), whose sum is σ = 202535424. Its totient is φ = 16953600.

The previous prime is 65172769. The next prime is 65172841. The reversal of 65172780 is 8727156.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2965 + ... + 11795.

It is an arithmetic number, because the mean of its divisors is an integer number (2812992).

Almost surely, 2^65172780 is an apocalyptic number.

65172780 is a gapful number since it is divisible by the number (60) 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 65172780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (101267712).

65172780 is an abundant number, since it is smaller than the sum of its proper divisors (137362644).

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

65172780 is a wasteful number, since it uses less digits than its factorization.

65172780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8887 (or 8882 counting only the distinct ones).

The product of its (nonzero) digits is 23520, while the sum is 36.

The square root of 65172780 is about 8072.9659976987. The cubic root of 65172780 is about 402.4285175837.

The spelling of 65172780 in words is "sixty-five million, one hundred seventy-two thousand, seven hundred eighty".