31857342978 has 16 divisors (see below), whose sum is σ = 67068090720. Its totient is φ = 10060213536.

The previous prime is 31857342971. The next prime is 31857342983. The reversal of 31857342978 is 87924375813.

It is a Harshad number since it is a multiple of its sum of digits (57).

It is not an unprimeable number, because it can be changed into a prime (31857342971) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 139725075 + ... + 139725302.

It is an arithmetic number, because the mean of its divisors is an integer number (4191755670).

Almost surely, 2^31857342978 is an apocalyptic number.

31857342978 is a gapful number since it is divisible by the number (38) formed by its first and last digit.

31857342978 is an abundant number, since it is smaller than the sum of its proper divisors (35210747742).

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

31857342978 is a wasteful number, since it uses less digits than its factorization.

31857342978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 279450401.

The product of its digits is 10160640, while the sum is 57.

The spelling of 31857342978 in words is "thirty-one billion, eight hundred fifty-seven million, three hundred forty-two thousand, nine hundred seventy-eight".