31720942 has 16 divisors (see below), whose sum is σ = 51994800. Its totient is φ = 14394240.

The previous prime is 31720939. The next prime is 31720943. The reversal of 31720942 is 24902713.

It is a super-2 number, since 2×31720942² = 2012436322734728, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 31720942.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31720943) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 21484 + ... + 22912.

It is an arithmetic number, because the mean of its divisors is an integer number (3249675).

Almost surely, 2^31720942 is an apocalyptic number.

31720942 is a deficient number, since it is larger than the sum of its proper divisors (20273858).

31720942 is a wasteful number, since it uses less digits than its factorization.

31720942 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2451.

The product of its (nonzero) digits is 3024, while the sum is 28.

The square root of 31720942 is about 5632.1347640127. The cubic root of 31720942 is about 316.5546460038.

The spelling of 31720942 in words is "thirty-one million, seven hundred twenty thousand, nine hundred forty-two".