31977540 has 144 divisors (see below), whose sum is σ = 113742720. Its totient is φ = 7119360.

The previous prime is 31977529. The next prime is 31977553. The reversal of 31977540 is 4577913.

It is a happy number.

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 = 31977495 and 31977504.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 51351 + ... + 51969.

It is an arithmetic number, because the mean of its divisors is an integer number (789880).

Almost surely, 2^31977540 is an apocalyptic number.

31977540 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31977540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (56871360).

31977540 is an abundant number, since it is smaller than the sum of its proper divisors (81765180).

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

31977540 is a wasteful number, since it uses less digits than its factorization.

31977540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 682 (or 677 counting only the distinct ones).

The product of its (nonzero) digits is 26460, while the sum is 36.

The square root of 31977540 is about 5654.8686987409. The cubic root of 31977540 is about 317.4059158682.

Adding to 31977540 its product of nonzero digits (26460), we get a triangular number (32004000 = T₈₀₀₀).

The spelling of 31977540 in words is "thirty-one million, nine hundred seventy-seven thousand, five hundred forty".