77681925 has 72 divisors (see below), whose sum is σ = 153900864. Its totient is φ = 37255680.

The previous prime is 77681917. The next prime is 77681927. The reversal of 77681925 is 52918677.

It is not a de Polignac number, because 77681925 - 2³ = 77681917 is a prime.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77681927) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 87534 + ... + 88416.

It is an arithmetic number, because the mean of its divisors is an integer number (2137512).

Almost surely, 2^77681925 is an apocalyptic number.

77681925 is a gapful number since it is divisible by the number (75) formed by its first and last digit.

It is an amenable number.

77681925 is a deficient number, since it is larger than the sum of its proper divisors (76218939).

77681925 is a wasteful number, since it uses less digits than its factorization.

77681925 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 939 (or 931 counting only the distinct ones).

The product of its digits is 211680, while the sum is 45.

The square root of 77681925 is about 8813.7350198426. The cubic root of 77681925 is about 426.6842966212.

Subtracting from 77681925 its sum of digits (45), we obtain a triangular number (77681880 = T₁₂₄₆₄).

It can be divided in two parts, 77681 and 925, that added together give a triangular number (78606 = T₃₉₆).

The spelling of 77681925 in words is "seventy-seven million, six hundred eighty-one thousand, nine hundred twenty-five".