21125405415 has 16 divisors (see below), whose sum is σ = 34438398048. Its totient is φ = 11054299776.

The previous prime is 21125405393. The next prime is 21125405423. The reversal of 21125405415 is 51450452112.

It is not a de Polignac number, because 21125405415 - 2⁵ = 21125405383 is a prime.

It is a super-2 number, since 2×21125405415² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13285624 + ... + 13287213.

It is an arithmetic number, because the mean of its divisors is an integer number (2152399878).

Almost surely, 2^21125405415 is an apocalyptic number.

21125405415 is a deficient number, since it is larger than the sum of its proper divisors (13312992633).

21125405415 is a wasteful number, since it uses less digits than its factorization.

21125405415 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26572898.

The product of its (nonzero) digits is 8000, while the sum is 30.

Adding to 21125405415 its reverse (51450452112), we get a palindrome (72575857527).

The spelling of 21125405415 in words is "twenty-one billion, one hundred twenty-five million, four hundred five thousand, four hundred fifteen".