25431437661 has 32 divisors (see below), whose sum is σ = 41894799360. Its totient is φ = 13395295296.

The previous prime is 25431437641. The next prime is 25431437687. The reversal of 25431437661 is 16673413452.

It is not a de Polignac number, because 25431437661 - 2⁷ = 25431437533 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25431437641) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 846561 + ... + 876086.

It is an arithmetic number, because the mean of its divisors is an integer number (1309212480).

Almost surely, 2^25431437661 is an apocalyptic number.

25431437661 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

25431437661 is a deficient number, since it is larger than the sum of its proper divisors (16463361699).

25431437661 is a wasteful number, since it uses less digits than its factorization.

25431437661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1722713.

The product of its digits is 362880, while the sum is 42.

The spelling of 25431437661 in words is "twenty-five billion, four hundred thirty-one million, four hundred thirty-seven thousand, six hundred sixty-one".