21719739139 has 4 divisors (see below), whose sum is σ = 24822559024. Its totient is φ = 18616919256.

The previous prime is 21719739131. The next prime is 21719739161. The reversal of 21719739139 is 93193791712.

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 21719739139 - 2³ = 21719739131 is a prime.

It is a super-2 number, since 2×21719739139² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21719739131) 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, 1551409932 + ... + 1551409945.

It is an arithmetic number, because the mean of its divisors is an integer number (6205639756).

Almost surely, 2^21719739139 is an apocalyptic number.

21719739139 is a deficient number, since it is larger than the sum of its proper divisors (3102819885).

21719739139 is an equidigital number, since it uses as much as digits as its factorization.

21719739139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3102819884.

The product of its digits is 642978, while the sum is 52.

The spelling of 21719739139 in words is "twenty-one billion, seven hundred nineteen million, seven hundred thirty-nine thousand, one hundred thirty-nine".