21492391562879 has 4 divisors (see below), whose sum is σ = 21492405722184. Its totient is φ = 21492377403576.

The previous prime is 21492391562819. The next prime is 21492391562881. The reversal of 21492391562879 is 97826519329412.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21492391562879 is a prime.

It is a super-2 number, since 2×21492391562879² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21492391562819) 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, 4486097 + ... + 7944170.

It is an arithmetic number, because the mean of its divisors is an integer number (5373101430546).

Almost surely, 2^{21492391562879} is an apocalyptic number.

21492391562879 is a deficient number, since it is larger than the sum of its proper divisors (14159305).

21492391562879 is a wasteful number, since it uses less digits than its factorization.

21492391562879 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14159304.

The product of its digits is 117573120, while the sum is 68.

The spelling of 21492391562879 in words is "twenty-one trillion, four hundred ninety-two billion, three hundred ninety-one million, five hundred sixty-two thousand, eight hundred seventy-nine".