25551621 has 6 divisors (see below), whose sum is σ = 36907910. Its totient is φ = 17034408.

The previous prime is 25551613. The next prime is 25551623. The reversal of 25551621 is 12615552.

It can be written as a sum of positive squares in only one way, i.e., 24147396 + 1404225 = 4914^2 + 1185^2 .

It is not a de Polignac number, because 25551621 - 2³ = 25551613 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25551623) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1419526 + ... + 1419543.

Almost surely, 2^25551621 is an apocalyptic number.

It is an amenable number.

25551621 is a deficient number, since it is larger than the sum of its proper divisors (11356289).

25551621 is a wasteful number, since it uses less digits than its factorization.

25551621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2839075 (or 2839072 counting only the distinct ones).

The product of its digits is 3000, while the sum is 27.

The square root of 25551621 is about 5054.8611256888. The cubic root of 25551621 is about 294.5367468172.

The spelling of 25551621 in words is "twenty-five million, five hundred fifty-one thousand, six hundred twenty-one".