31722521 has 2 divisors, whose sum is σ = 31722522. Its totient is φ = 31722520.

The previous prime is 31722503. The next prime is 31722539. The reversal of 31722521 is 12522713.

It is a happy number.

It is a balanced prime because it is at equal distance from previous prime (31722503) and next prime (31722539).

It can be written as a sum of positive squares in only one way, i.e., 26265625 + 5456896 = 5125^2 + 2336^2 .

It is a cyclic number.

It is not a de Polignac number, because 31722521 - 2¹⁰ = 31721497 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (31722541) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15861260 + 15861261.

It is an arithmetic number, because the mean of its divisors is an integer number (15861261).

Almost surely, 2^31722521 is an apocalyptic number.

It is an amenable number.

31722521 is a deficient number, since it is larger than the sum of its proper divisors (1).

31722521 is an equidigital number, since it uses as much as digits as its factorization.

31722521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 840, while the sum is 23.

The square root of 31722521 is about 5632.2749400220. The cubic root of 31722521 is about 316.5598983855.

The spelling of 31722521 in words is "thirty-one million, seven hundred twenty-two thousand, five hundred twenty-one".