31060721 has 2 divisors, whose sum is σ = 31060722. Its totient is φ = 31060720.

The previous prime is 31060699. The next prime is 31060759. The reversal of 31060721 is 12706013.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 26061025 + 4999696 = 5105^2 + 2236^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31060721 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 31060693 and 31060702.

It is not a weakly prime, because it can be changed into another prime (31060121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15530360 + 15530361.

It is an arithmetic number, because the mean of its divisors is an integer number (15530361).

Almost surely, 2^31060721 is an apocalyptic number.

It is an amenable number.

31060721 is a deficient number, since it is larger than the sum of its proper divisors (1).

31060721 is an equidigital number, since it uses as much as digits as its factorization.

31060721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 252, while the sum is 20.

The square root of 31060721 is about 5573.2146020048. The cubic root of 31060721 is about 314.3430366026.

Adding to 31060721 its reverse (12706013), we get a palindrome (43766734).

The spelling of 31060721 in words is "thirty-one million, sixty thousand, seven hundred twenty-one".