21351999999 has 16 divisors (see below), whose sum is σ = 31450590720. Its totient is φ = 12776799360.

The previous prime is 21351999961. The next prime is 21352000001. The reversal of 21351999999 is 99999915312.

It is not a de Polignac number, because 21351999999 - 2⁸ = 21351999743 is a prime.

21351999999 is a modest number, since divided by 999999 gives 21351 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21351999959) 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 15 ways as a sum of consecutive naturals, for example, 4092522 + ... + 4097735.

It is an arithmetic number, because the mean of its divisors is an integer number (1965661920).

Almost surely, 2^21351999999 is an apocalyptic number.

21351999999 is a deficient number, since it is larger than the sum of its proper divisors (10098590721).

21351999999 is a wasteful number, since it uses less digits than its factorization.

21351999999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8190350.

The product of its digits is 15943230, while the sum is 66.

The spelling of 21351999999 in words is "twenty-one billion, three hundred fifty-one million, nine hundred ninety-nine thousand, nine hundred ninety-nine".