71781920 has 48 divisors (see below), whose sum is σ = 193814208. Its totient is φ = 24610560.

The previous prime is 71781917. The next prime is 71781949. The reversal of 71781920 is 2918717.

It is a Harshad number since it is a multiple of its sum of digits (35).

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, 30926 + ... + 33165.

It is an arithmetic number, because the mean of its divisors is an integer number (4037796).

Almost surely, 2^71781920 is an apocalyptic number.

71781920 is a gapful number since it is divisible by the number (70) formed by its first and last digit.

It is an amenable number.

71781920 is an abundant number, since it is smaller than the sum of its proper divisors (122032288).

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

71781920 is a wasteful number, since it uses less digits than its factorization.

71781920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64113 (or 64105 counting only the distinct ones).

The product of its (nonzero) digits is 7056, while the sum is 35.

The square root of 71781920 is about 8472.4211415628. The cubic root of 71781920 is about 415.5963169759.

The spelling of 71781920 in words is "seventy-one million, seven hundred eighty-one thousand, nine hundred twenty".