77309440 has 160 divisors (see below), whose sum is σ = 210361536. Its totient is φ = 27033600.

The previous prime is 77309429. The next prime is 77309473. The reversal of 77309440 is 4490377.

It is a tau number, because it is divible by the number of its divisors (160).

It is a super-2 number, since 2×77309440² = 11953499026227200, which contains 22 as substring.

It is a Smith number, since the sum of its digits (34) coincides with the sum of the digits of its prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 77309396 and 77309405.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 765390 + ... + 765490.

Almost surely, 2^77309440 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 77309440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (105180768).

77309440 is an abundant number, since it is smaller than the sum of its proper divisors (133052096).

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

77309440 is a wasteful number, since it uses less digits than its factorization.

77309440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 160 (or 144 counting only the distinct ones).

The product of its (nonzero) digits is 21168, while the sum is 34.

The square root of 77309440 is about 8792.5786888717. The cubic root of 77309440 is about 426.0012196252.

The spelling of 77309440 in words is "seventy-seven million, three hundred nine thousand, four hundred forty".