25492021981 has 2 divisors, whose sum is σ = 25492021982. Its totient is φ = 25492021980.

The previous prime is 25492021969. The next prime is 25492021993. The reversal of 25492021981 is 18912029452.

It is a balanced prime because it is at equal distance from previous prime (25492021969) and next prime (25492021993).

It can be written as a sum of positive squares in only one way, i.e., 13257449881 + 12234572100 = 115141^2 + 110610^2 .

It is a cyclic number.

It is not a de Polignac number, because 25492021981 - 2⁹ = 25492021469 is a prime.

It is a super-2 number, since 2×25492021981² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25492021081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12746010990 + 12746010991.

It is an arithmetic number, because the mean of its divisors is an integer number (12746010991).

Almost surely, 2^25492021981 is an apocalyptic number.

It is an amenable number.

25492021981 is a deficient number, since it is larger than the sum of its proper divisors (1).

25492021981 is an equidigital number, since it uses as much as digits as its factorization.

25492021981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 103680, while the sum is 43.

The spelling of 25492021981 in words is "twenty-five billion, four hundred ninety-two million, twenty-one thousand, nine hundred eighty-one".