25630781 has 16 divisors (see below), whose sum is σ = 30336768. Its totient is φ = 21388800.

The previous prime is 25630777. The next prime is 25630789. The reversal of 25630781 is 18703652.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 25630781 - 2² = 25630777 is a prime.

It is a super-2 number, since 2×25630781² = 1313873869339922, 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 (25630789) 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, 5996 + ... + 9338.

It is an arithmetic number, because the mean of its divisors is an integer number (1896048).

Almost surely, 2^25630781 is an apocalyptic number.

It is an amenable number.

25630781 is a deficient number, since it is larger than the sum of its proper divisors (4705987).

25630781 is a wasteful number, since it uses less digits than its factorization.

25630781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3412.

The product of its (nonzero) digits is 10080, while the sum is 32.

The square root of 25630781 is about 5062.6851571078. The cubic root of 25630781 is about 294.8405956772.

The spelling of 25630781 in words is "twenty-five million, six hundred thirty thousand, seven hundred eighty-one".