20725631 has 2 divisors, whose sum is σ = 20725632. Its totient is φ = 20725630.

The previous prime is 20725619. The next prime is 20725667. The reversal of 20725631 is 13652702.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20725631 is a prime.

It is a super-2 number, since 2×20725631² = 859103560696322, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20725631.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20725931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10362815 + 10362816.

It is an arithmetic number, because the mean of its divisors is an integer number (10362816).

Almost surely, 2^20725631 is an apocalyptic number.

20725631 is a deficient number, since it is larger than the sum of its proper divisors (1).

20725631 is an equidigital number, since it uses as much as digits as its factorization.

20725631 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2520, while the sum is 26.

The square root of 20725631 is about 4552.5411585180. The cubic root of 20725631 is about 274.6856175917.

The spelling of 20725631 in words is "twenty million, seven hundred twenty-five thousand, six hundred thirty-one".