77870640 has 80 divisors (see below), whose sum is σ = 251912448. Its totient is φ = 19861248.

The previous prime is 77870627. The next prime is 77870651. The reversal of 77870640 is 4607877.

77870640 = T₄₀ + T₄₁ + ... + T₇₇₅.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (80).

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, 1534 + ... + 12573.

Almost surely, 2^77870640 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 77870640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (125956224).

77870640 is an abundant number, since it is smaller than the sum of its proper divisors (174041808).

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

77870640 is a wasteful number, since it uses less digits than its factorization.

77870640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14146 (or 14140 counting only the distinct ones).

The product of its (nonzero) digits is 65856, while the sum is 39.

The square root of 77870640 is about 8824.4342594866. The cubic root of 77870640 is about 427.0295361361.

The spelling of 77870640 in words is "seventy-seven million, eight hundred seventy thousand, six hundred forty".