31397131 has 4 divisors (see below), whose sum is σ = 31608000. Its totient is φ = 31186264.

The previous prime is 31397129. The next prime is 31397143. The reversal of 31397131 is 13179313.

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 31397131 - 2¹ = 31397129 is a prime.

It is a super-2 number, since 2×31397131² = 1971559670062322, which contains 22 as substring.

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 31397131.

It is not an unprimeable number, because it can be changed into a prime (31397161) 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, 105211 + ... + 105508.

It is an arithmetic number, because the mean of its divisors is an integer number (7902000).

Almost surely, 2^31397131 is an apocalyptic number.

31397131 is a deficient number, since it is larger than the sum of its proper divisors (210869).

31397131 is a wasteful number, since it uses less digits than its factorization.

31397131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 210868.

The product of its digits is 1701, while the sum is 28.

The square root of 31397131 is about 5603.3142870983. The cubic root of 31397131 is about 315.4738178817.

The spelling of 31397131 in words is "thirty-one million, three hundred ninety-seven thousand, one hundred thirty-one".