25340401981 has 2 divisors, whose sum is σ = 25340401982. Its totient is φ = 25340401980.

The previous prime is 25340401979. The next prime is 25340402023. The reversal of 25340401981 is 18910404352.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 23199859225 + 2140542756 = 152315^2 + 46266^2 .

It is a cyclic number.

It is not a de Polignac number, because 25340401981 - 2¹ = 25340401979 is a prime.

It is a super-2 number, since 2×25340401981² (a number of 22 digits) contains 22 as substring.

Together with 25340401979, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 25340401981.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25340401921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12670200990 + 12670200991.

It is an arithmetic number, because the mean of its divisors is an integer number (12670200991).

Almost surely, 2^25340401981 is an apocalyptic number.

It is an amenable number.

25340401981 is a deficient number, since it is larger than the sum of its proper divisors (1).

25340401981 is an equidigital number, since it uses as much as digits as its factorization.

25340401981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 34560, while the sum is 37.

The spelling of 25340401981 in words is "twenty-five billion, three hundred forty million, four hundred one thousand, nine hundred eighty-one".