25978721 has 2 divisors, whose sum is σ = 25978722. Its totient is φ = 25978720.

The previous prime is 25978717. The next prime is 25978727. The reversal of 25978721 is 12787952.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14145121 + 11833600 = 3761^2 + 3440^2 .

It is a cyclic number.

It is not a de Polignac number, because 25978721 - 2² = 25978717 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (25978727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12989360 + 12989361.

It is an arithmetic number, because the mean of its divisors is an integer number (12989361).

Almost surely, 2^25978721 is an apocalyptic number.

It is an amenable number.

25978721 is a deficient number, since it is larger than the sum of its proper divisors (1).

25978721 is an equidigital number, since it uses as much as digits as its factorization.

25978721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 70560, while the sum is 41.

The square root of 25978721 is about 5096.9325088724. The cubic root of 25978721 is about 296.1687656110.

The spelling of 25978721 in words is "twenty-five million, nine hundred seventy-eight thousand, seven hundred twenty-one".