21451251373 has 16 divisors (see below), whose sum is σ = 22532190912. Its totient is φ = 20398896000.

The previous prime is 21451251361. The next prime is 21451251383. The reversal of 21451251373 is 37315215412.

It is a cyclic number.

It is not a de Polignac number, because 21451251373 - 2³³ = 12861316781 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21451251383) 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, 853243 + ... + 878023.

It is an arithmetic number, because the mean of its divisors is an integer number (1408261932).

Almost surely, 2^21451251373 is an apocalyptic number.

It is an amenable number.

21451251373 is a deficient number, since it is larger than the sum of its proper divisors (1080939539).

21451251373 is a wasteful number, since it uses less digits than its factorization.

21451251373 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25356.

The product of its digits is 25200, while the sum is 34.

Adding to 21451251373 its reverse (37315215412), we get a palindrome (58766466785).

The spelling of 21451251373 in words is "twenty-one billion, four hundred fifty-one million, two hundred fifty-one thousand, three hundred seventy-three".