21125254351 has 4 divisors (see below), whose sum is σ = 21217504600. Its totient is φ = 21033004104.

The previous prime is 21125254313. The next prime is 21125254411. The reversal of 21125254351 is 15345252112.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21125254351 - 2¹⁹ = 21124730063 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21125254151) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 46124781 + ... + 46125238.

It is an arithmetic number, because the mean of its divisors is an integer number (5304376150).

Almost surely, 2^21125254351 is an apocalyptic number.

21125254351 is a deficient number, since it is larger than the sum of its proper divisors (92250249).

21125254351 is an equidigital number, since it uses as much as digits as its factorization.

21125254351 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 92250248.

The product of its digits is 12000, while the sum is 31.

The spelling of 21125254351 in words is "twenty-one billion, one hundred twenty-five million, two hundred fifty-four thousand, three hundred fifty-one".