77471640 has 80 divisors (see below), whose sum is σ = 260401680. Its totient is φ = 20658240.

The previous prime is 77471627. The next prime is 77471657. The reversal of 77471640 is 4617477.

77471640 is a `hidden beast` number, since 7 + 7 + 4 + 7 + 1 + 640 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 77471595 and 77471604.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 8716 + ... + 15195.

It is an arithmetic number, because the mean of its divisors is an integer number (3255021).

Almost surely, 2^77471640 is an apocalyptic number.

It is an amenable number.

77471640 is an abundant number, since it is smaller than the sum of its proper divisors (182930040).

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

77471640 is a wasteful number, since it uses less digits than its factorization.

77471640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23934 (or 23921 counting only the distinct ones).

The product of its (nonzero) digits is 32928, while the sum is 36.

The square root of 77471640 is about 8801.7975436839. The cubic root of 77471640 is about 426.2989371723.

The spelling of 77471640 in words is "seventy-seven million, four hundred seventy-one thousand, six hundred forty".