77870820 has 24 divisors (see below), whose sum is σ = 218038464. Its totient is φ = 20765536.

The previous prime is 77870809. The next prime is 77870839. The reversal of 77870820 is 2807877.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 648864 + ... + 648983.

It is an arithmetic number, because the mean of its divisors is an integer number (9084936).

Almost surely, 2^77870820 is an apocalyptic number.

It is an amenable number.

77870820 is an abundant number, since it is smaller than the sum of its proper divisors (140167644).

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

77870820 is a wasteful number, since it uses less digits than its factorization.

77870820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1297859 (or 1297857 counting only the distinct ones).

The product of its (nonzero) digits is 43904, while the sum is 39.

The square root of 77870820 is about 8824.4444584348. Note that the first 4 decimals coincide. The cubic root of 77870820 is about 427.0298651657.

The spelling of 77870820 in words is "seventy-seven million, eight hundred seventy thousand, eight hundred twenty".