21523125264461 has 4 divisors (see below), whose sum is σ = 21566960550624. Its totient is φ = 21479289978300.

The previous prime is 21523125264449. The next prime is 21523125264503. The reversal of 21523125264461 is 16446252132512.

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 not a de Polignac number, because 21523125264461 - 2¹⁴ = 21523125248077 is a prime.

It is a super-2 number, since 2×21523125264461² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21523125264401) 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, 21917642345 + ... + 21917643326.

It is an arithmetic number, because the mean of its divisors is an integer number (5391740137656).

Almost surely, 2^{21523125264461} is an apocalyptic number.

It is an amenable number.

21523125264461 is a deficient number, since it is larger than the sum of its proper divisors (43835286163).

21523125264461 is an equidigital number, since it uses as much as digits as its factorization.

21523125264461 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43835286162.

The product of its digits is 691200, while the sum is 44.

Adding to 21523125264461 its reverse (16446252132512), we get a palindrome (37969377396973).

The spelling of 21523125264461 in words is "twenty-one trillion, five hundred twenty-three billion, one hundred twenty-five million, two hundred sixty-four thousand, four hundred sixty-one".