21151525451405 has 4 divisors (see below), whose sum is σ = 25381830541692. Its totient is φ = 16921220361120.

The previous prime is 21151525451401. The next prime is 21151525451447. The reversal of 21151525451405 is 50415452515112.

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

It can be written as a sum of positive squares in 2 ways, for example, as 2251734334084 + 18899791117321 = 1500578^2 + 4347389^2 .

It is not a de Polignac number, because 21151525451405 - 2² = 21151525451401 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 (21151525451401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2115152545136 + ... + 2115152545145.

It is an arithmetic number, because the mean of its divisors is an integer number (6345457635423).

Almost surely, 2^{21151525451405} is an apocalyptic number.

It is an amenable number.

21151525451405 is a deficient number, since it is larger than the sum of its proper divisors (4230305090287).

21151525451405 is an equidigital number, since it uses as much as digits as its factorization.

21151525451405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4230305090286.

The product of its (nonzero) digits is 200000, while the sum is 41.

Adding to 21151525451405 its reverse (50415452515112), we get a palindrome (71566977966517).

The spelling of 21151525451405 in words is "twenty-one trillion, one hundred fifty-one billion, five hundred twenty-five million, four hundred fifty-one thousand, four hundred five".