21404621554507 has 4 divisors (see below), whose sum is σ = 21411479815096. Its totient is φ = 21397763293920.

The previous prime is 21404621554493. The next prime is 21404621554529. The reversal of 21404621554507 is 70545512640412.

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 21404621554507 - 2¹⁵ = 21404621521739 is a prime.

It is a super-2 number, since 2×21404621554507² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21404621554577) 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, 3429125613 + ... + 3429131854.

It is an arithmetic number, because the mean of its divisors is an integer number (5352869953774).

Almost surely, 2^{21404621554507} is an apocalyptic number.

21404621554507 is a deficient number, since it is larger than the sum of its proper divisors (6858260589).

21404621554507 is an equidigital number, since it uses as much as digits as its factorization.

21404621554507 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6858260588.

The product of its (nonzero) digits is 1344000, while the sum is 46.

The spelling of 21404621554507 in words is "twenty-one trillion, four hundred four billion, six hundred twenty-one million, five hundred fifty-four thousand, five hundred seven".