25253021021 has 4 divisors (see below), whose sum is σ = 25254843552. Its totient is φ = 25251198492.

The previous prime is 25253021009. The next prime is 25253021023. The reversal of 25253021021 is 12012035252.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-25253021021 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 (25253021023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 890321 + ... + 918246.

It is an arithmetic number, because the mean of its divisors is an integer number (6313710888).

Almost surely, 2^25253021021 is an apocalyptic number.

It is an amenable number.

25253021021 is a deficient number, since it is larger than the sum of its proper divisors (1822531).

25253021021 is a wasteful number, since it uses less digits than its factorization.

25253021021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1822530.

The product of its (nonzero) digits is 1200, while the sum is 23.

Adding to 25253021021 its reverse (12012035252), we get a palindrome (37265056273).

The spelling of 25253021021 in words is "twenty-five billion, two hundred fifty-three million, twenty-one thousand, twenty-one".