31477021 has 2 divisors, whose sum is σ = 31477022. Its totient is φ = 31477020.

The previous prime is 31476959. The next prime is 31477027. The reversal of 31477021 is 12077413.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 31236921 + 240100 = 5589^2 + 490^2 .

It is a cyclic number.

It is not a de Polignac number, because 31477021 - 2⁹ = 31476509 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31477027) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15738510 + 15738511.

It is an arithmetic number, because the mean of its divisors is an integer number (15738511).

Almost surely, 2^31477021 is an apocalyptic number.

It is an amenable number.

31477021 is a deficient number, since it is larger than the sum of its proper divisors (1).

31477021 is an equidigital number, since it uses as much as digits as its factorization.

31477021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1176, while the sum is 25.

The square root of 31477021 is about 5610.4385746571. The cubic root of 31477021 is about 315.7411656314.

The spelling of 31477021 in words is "thirty-one million, four hundred seventy-seven thousand, twenty-one".