31220689 has 4 divisors (see below), whose sum is σ = 32227840. Its totient is φ = 30213540.

The previous prime is 31220681. The next prime is 31220701. The reversal of 31220689 is 98602213.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 31220689 - 2³ = 31220681 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (31), and also a Moran number because the ratio is a prime number: 1007119 = 31220689 / (3 + 1 + 2 + 2 + 0 + 6 + 8 + 9).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 31220689.

It is not an unprimeable number, because it can be changed into a prime (31220681) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 503529 + ... + 503590.

It is an arithmetic number, because the mean of its divisors is an integer number (8056960).

Almost surely, 2^31220689 is an apocalyptic number.

It is an amenable number.

31220689 is a deficient number, since it is larger than the sum of its proper divisors (1007151).

31220689 is a wasteful number, since it uses less digits than its factorization.

31220689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1007150.

The product of its (nonzero) digits is 5184, while the sum is 31.

The square root of 31220689 is about 5587.5476731747. The cubic root of 31220689 is about 314.8817528792.

The spelling of 31220689 in words is "thirty-one million, two hundred twenty thousand, six hundred eighty-nine".