31399691 has 8 divisors (see below), whose sum is σ = 32095440. Its totient is φ = 30707872.

The previous prime is 31399661. The next prime is 31399729. The reversal of 31399691 is 19699313.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 31399691 - 2¹⁰ = 31398667 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31399601) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19856 + ... + 21378.

It is an arithmetic number, because the mean of its divisors is an integer number (4011930).

Almost surely, 2^31399691 is an apocalyptic number.

31399691 is a deficient number, since it is larger than the sum of its proper divisors (695749).

31399691 is a wasteful number, since it uses less digits than its factorization.

31399691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1965.

The product of its digits is 39366, while the sum is 41.

The square root of 31399691 is about 5603.5427186736. The cubic root of 31399691 is about 315.4823918182.

The spelling of 31399691 in words is "thirty-one million, three hundred ninety-nine thousand, six hundred ninety-one".