31220387 has 4 divisors (see below), whose sum is σ = 34058616. Its totient is φ = 28382160.

The previous prime is 31220383. The next prime is 31220419. The reversal of 31220387 is 78302213.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 31220387 - 2² = 31220383 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31220383) 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 3 ways as a sum of consecutive naturals, for example, 1419098 + ... + 1419119.

It is an arithmetic number, because the mean of its divisors is an integer number (8514654).

Almost surely, 2^31220387 is an apocalyptic number.

31220387 is a deficient number, since it is larger than the sum of its proper divisors (2838229).

31220387 is a wasteful number, since it uses less digits than its factorization.

31220387 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2838228.

The product of its (nonzero) digits is 2016, while the sum is 26.

The square root of 31220387 is about 5587.5206487314. The cubic root of 31220387 is about 314.8807375845.

The spelling of 31220387 in words is "thirty-one million, two hundred twenty thousand, three hundred eighty-seven".