21312245051 has 4 divisors (see below), whose sum is σ = 21888251712. Its totient is φ = 20736238392.

The previous prime is 21312245021. The next prime is 21312245057. The reversal of 21312245051 is 15054221312.

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

It is a cyclic number.

It is not a de Polignac number, because 21312245051 - 2¹⁴ = 21312228667 is a prime.

It is a super-2 number, since 2×21312245051² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21312245051.

It is not an unprimeable number, because it can be changed into a prime (21312245057) 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, 288003275 + ... + 288003348.

It is an arithmetic number, because the mean of its divisors is an integer number (5472062928).

Almost surely, 2^21312245051 is an apocalyptic number.

21312245051 is a deficient number, since it is larger than the sum of its proper divisors (576006661).

21312245051 is an equidigital number, since it uses as much as digits as its factorization.

21312245051 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 576006660.

The product of its (nonzero) digits is 2400, while the sum is 26.

Adding to 21312245051 its reverse (15054221312), we get a palindrome (36366466363).

The spelling of 21312245051 in words is "twenty-one billion, three hundred twelve million, two hundred forty-five thousand, fifty-one".