25631021 has 8 divisors (see below), whose sum is σ = 27914040. Its totient is φ = 23392512.

The previous prime is 25630991. The next prime is 25631029. The reversal of 25631021 is 12013652.

It can be written as a sum of positive squares in 4 ways, for example, as 1473796 + 24157225 = 1214^2 + 4915^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 25631021 - 2¹⁴ = 25614637 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 25630984 and 25631002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25631029) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9920 + ... + 12233.

It is an arithmetic number, because the mean of its divisors is an integer number (3489255).

Almost surely, 2^25631021 is an apocalyptic number.

It is an amenable number.

25631021 is a deficient number, since it is larger than the sum of its proper divisors (2283019).

25631021 is a wasteful number, since it uses less digits than its factorization.

25631021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22255.

The product of its (nonzero) digits is 360, while the sum is 20.

The square root of 25631021 is about 5062.7088598891. The cubic root of 25631021 is about 294.8415159447.

Adding to 25631021 its reverse (12013652), we get a palindrome (37644673).

The spelling of 25631021 in words is "twenty-five million, six hundred thirty-one thousand, twenty-one".