77491980 has 36 divisors (see below), whose sum is σ = 235059552. Its totient is φ = 20664480.

The previous prime is 77491979. The next prime is 77492011. The reversal of 77491980 is 8919477.

77491980 is a `hidden beast` number, since 77 + 491 + 98 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

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

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 215076 + ... + 215435.

It is an arithmetic number, because the mean of its divisors is an integer number (6529432).

Almost surely, 2^77491980 is an apocalyptic number.

It is an amenable number.

77491980 is an abundant number, since it is smaller than the sum of its proper divisors (157567572).

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

77491980 is a wasteful number, since it uses less digits than its factorization.

77491980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 430526 (or 430521 counting only the distinct ones).

The product of its (nonzero) digits is 127008, while the sum is 45.

The square root of 77491980 is about 8802.9529136535. The cubic root of 77491980 is about 426.3362418412.

The spelling of 77491980 in words is "seventy-seven million, four hundred ninety-one thousand, nine hundred eighty".