21207637507 has 8 divisors (see below), whose sum is σ = 24238363232. Its totient is φ = 18177177600.

The previous prime is 21207637499. The next prime is 21207637523. The reversal of 21207637507 is 70573670212.

It is a happy number.

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 21207637507 - 2³ = 21207637499 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21207637507.

It is not an unprimeable number, because it can be changed into a prime (21207637537) 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, 152707 + ... + 256387.

It is an arithmetic number, because the mean of its divisors is an integer number (3029795404).

Almost surely, 2^21207637507 is an apocalyptic number.

21207637507 is a deficient number, since it is larger than the sum of its proper divisors (3030725725).

21207637507 is a wasteful number, since it uses less digits than its factorization.

21207637507 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 132909.

The product of its (nonzero) digits is 123480, while the sum is 40.

The spelling of 21207637507 in words is "twenty-one billion, two hundred seven million, six hundred thirty-seven thousand, five hundred seven".