21604613837 has 4 divisors (see below), whose sum is σ = 22301536896. Its totient is φ = 20907690780.

The previous prime is 21604613831. The next prime is 21604613839. The reversal of 21604613837 is 73831640612.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21604613837 - 2¹⁴ = 21604597453 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21604613794 and 21604613803.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21604613831) 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, 348461483 + ... + 348461544.

It is an arithmetic number, because the mean of its divisors is an integer number (5575384224).

Almost surely, 2^21604613837 is an apocalyptic number.

It is an amenable number.

21604613837 is a deficient number, since it is larger than the sum of its proper divisors (696923059).

21604613837 is an equidigital number, since it uses as much as digits as its factorization.

21604613837 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 696923058.

The product of its (nonzero) digits is 145152, while the sum is 41.

The spelling of 21604613837 in words is "twenty-one billion, six hundred four million, six hundred thirteen thousand, eight hundred thirty-seven".