21431615105 has 4 divisors (see below), whose sum is σ = 25717938132. Its totient is φ = 17145292080.

The previous prime is 21431615069. The next prime is 21431615147. The reversal of 21431615105 is 50151613412.

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 13799670784 + 7631944321 = 117472^2 + 87361^2 .

It is not a de Polignac number, because 21431615105 - 2⁸ = 21431614849 is a prime.

It is a super-2 number, since 2×21431615105² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2143161506 + ... + 2143161515.

It is an arithmetic number, because the mean of its divisors is an integer number (6429484533).

Almost surely, 2^21431615105 is an apocalyptic number.

It is an amenable number.

21431615105 is a deficient number, since it is larger than the sum of its proper divisors (4286323027).

21431615105 is an equidigital number, since it uses as much as digits as its factorization.

21431615105 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4286323026.

The product of its (nonzero) digits is 3600, while the sum is 29.

The spelling of 21431615105 in words is "twenty-one billion, four hundred thirty-one million, six hundred fifteen thousand, one hundred five".