21151213115 has 4 divisors (see below), whose sum is σ = 25381455744. Its totient is φ = 16920970488.

The previous prime is 21151213099. The next prime is 21151213189. The reversal of 21151213115 is 51131215112.

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 21151213115 - 2⁴ = 21151213099 is a prime.

It is a super-2 number, since 2×21151213115² (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, 2115121307 + ... + 2115121316.

It is an arithmetic number, because the mean of its divisors is an integer number (6345363936).

Almost surely, 2^21151213115 is an apocalyptic number.

21151213115 is a deficient number, since it is larger than the sum of its proper divisors (4230242629).

21151213115 is an equidigital number, since it uses as much as digits as its factorization.

21151213115 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4230242628.

The product of its digits is 300, while the sum is 23.

Adding to 21151213115 its reverse (51131215112), we get a palindrome (72282428227).

The spelling of 21151213115 in words is "twenty-one billion, one hundred fifty-one million, two hundred thirteen thousand, one hundred fifteen".