77977440 has 72 divisors (see below), whose sum is σ = 266102928. Its totient is φ = 20793600.

The previous prime is 77977423. The next prime is 77977513. The reversal of 77977440 is 4477977.

It is a tau number, because it is divible by the number of its divisors (72).

It is a super-2 number, since 2×77977440² = 12160962297907200, which contains 22 as substring.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 25636 + ... + 28515.

It is an arithmetic number, because the mean of its divisors is an integer number (3695874).

Almost surely, 2^77977440 is an apocalyptic number.

It is an amenable number.

77977440 is an abundant number, since it is smaller than the sum of its proper divisors (188125488).

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

77977440 is a wasteful number, since it uses less digits than its factorization.

77977440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54172 (or 54161 counting only the distinct ones).

The product of its (nonzero) digits is 345744, while the sum is 45.

The square root of 77977440 is about 8830.4835654680. The cubic root of 77977440 is about 427.2246713858.

The spelling of 77977440 in words is "seventy-seven million, nine hundred seventy-seven thousand, four hundred forty".