21489431979 has 8 divisors (see below), whose sum is σ = 29262205440. Its totient is φ = 14021473256.

The previous prime is 21489431947. The next prime is 21489431989. The reversal of 21489431979 is 97913498412.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21489431979 - 2⁵ = 21489431947 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21489431989) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 76203519 + ... + 76203800.

It is an arithmetic number, because the mean of its divisors is an integer number (3657775680).

Almost surely, 2^21489431979 is an apocalyptic number.

21489431979 is a deficient number, since it is larger than the sum of its proper divisors (7772773461).

21489431979 is a wasteful number, since it uses less digits than its factorization.

21489431979 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 152407369.

The product of its digits is 3919104, while the sum is 57.

The spelling of 21489431979 in words is "twenty-one billion, four hundred eighty-nine million, four hundred thirty-one thousand, nine hundred seventy-nine".