21491339007 has 4 divisors (see below), whose sum is σ = 28655118680. Its totient is φ = 14327559336.

The previous prime is 21491339003. The next prime is 21491339011. The reversal of 21491339007 is 70093319412.

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

It is an interprime number because it is at equal distance from previous prime (21491339003) and next prime (21491339011).

It is not a de Polignac number, because 21491339007 - 2² = 21491339003 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21491339003) 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, 3581889832 + ... + 3581889837.

It is an arithmetic number, because the mean of its divisors is an integer number (7163779670).

Almost surely, 2^21491339007 is an apocalyptic number.

21491339007 is a deficient number, since it is larger than the sum of its proper divisors (7163779673).

21491339007 is an equidigital number, since it uses as much as digits as its factorization.

21491339007 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7163779672.

The product of its (nonzero) digits is 40824, while the sum is 39.

The spelling of 21491339007 in words is "twenty-one billion, four hundred ninety-one million, three hundred thirty-nine thousand, seven".