31606661 has 2 divisors, whose sum is σ = 31606662. Its totient is φ = 31606660.

The previous prime is 31606657. The next prime is 31606667. The reversal of 31606661 is 16660613.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 31013761 + 592900 = 5569^2 + 770^2 .

It is an emirp because it is prime and its reverse (16660613) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31606661 - 2² = 31606657 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31606667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15803330 + 15803331.

It is an arithmetic number, because the mean of its divisors is an integer number (15803331).

Almost surely, 2^31606661 is an apocalyptic number.

It is an amenable number.

31606661 is a deficient number, since it is larger than the sum of its proper divisors (1).

31606661 is an equidigital number, since it uses as much as digits as its factorization.

31606661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3888, while the sum is 29.

The square root of 31606661 is about 5621.9801671653. The cubic root of 31606661 is about 316.1740382166.

The spelling of 31606661 in words is "thirty-one million, six hundred six thousand, six hundred sixty-one".