21451178679 has 16 divisors (see below), whose sum is σ = 33382990848. Its totient is φ = 11997011232.

The previous prime is 21451178669. The next prime is 21451178681. The reversal of 21451178679 is 97687115412.

It is a de Polignac number, because none of the positive numbers 2^k-21451178679 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21451178669) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10865872 + ... + 10867845.

It is an arithmetic number, because the mean of its divisors is an integer number (2086436928).

Almost surely, 2^21451178679 is an apocalyptic number.

21451178679 is a deficient number, since it is larger than the sum of its proper divisors (11931812169).

21451178679 is a wasteful number, since it uses less digits than its factorization.

21451178679 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21733774.

The product of its digits is 846720, while the sum is 51.

The spelling of 21451178679 in words is "twenty-one billion, four hundred fifty-one million, one hundred seventy-eight thousand, six hundred seventy-nine".