21310051 has 12 divisors (see below), whose sum is σ = 25590720. Its totient is φ = 17675280.

The previous prime is 21310049. The next prime is 21310057. The reversal of 21310051 is 15001312.

21310051 = 109² + 110² + ... + 402².

It is not a de Polignac number, because 21310051 - 2¹ = 21310049 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21310057) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5496 + ... + 8533.

It is an arithmetic number, because the mean of its divisors is an integer number (2132560).

Almost surely, 2^21310051 is an apocalyptic number.

21310051 is a deficient number, since it is larger than the sum of its proper divisors (4280669).

21310051 is a wasteful number, since it uses less digits than its factorization.

21310051 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14074 (or 14067 counting only the distinct ones).

The product of its (nonzero) digits is 30, while the sum is 13.

The square root of 21310051 is about 4616.2810789639. The cubic root of 21310051 is about 277.2435788371.

Adding to 21310051 its reverse (15001312), we get a palindrome (36311363).

The spelling of 21310051 in words is "twenty-one million, three hundred ten thousand, fifty-one".