25430781 has 16 divisors (see below), whose sum is σ = 34489728. Its totient is φ = 16665600.

The previous prime is 25430777. The next prime is 25430789. The reversal of 25430781 is 18703452.

It is not a de Polignac number, because 25430781 - 2² = 25430777 is a prime.

It is a super-2 number, since 2×25430781² = 1293449244539922, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25430789) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 81616 + ... + 81926.

It is an arithmetic number, because the mean of its divisors is an integer number (2155608).

Almost surely, 2^25430781 is an apocalyptic number.

It is an amenable number.

25430781 is a deficient number, since it is larger than the sum of its proper divisors (9058947).

25430781 is a wasteful number, since it uses less digits than its factorization.

25430781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 692.

The product of its (nonzero) digits is 6720, while the sum is 30.

The square root of 25430781 is about 5042.8941095367. The cubic root of 25430781 is about 294.0717003152.

The spelling of 25430781 in words is "twenty-five million, four hundred thirty thousand, seven hundred eighty-one".