21620405363 has 4 divisors (see below), whose sum is σ = 21621475848. Its totient is φ = 21619334880.

The previous prime is 21620405327. The next prime is 21620405419. The reversal of 21620405363 is 36350402612.

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 21620405363 - 2¹⁰ = 21620404339 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21620425363) 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, 504353 + ... + 545538.

It is an arithmetic number, because the mean of its divisors is an integer number (5405368962).

Almost surely, 2^21620405363 is an apocalyptic number.

21620405363 is a deficient number, since it is larger than the sum of its proper divisors (1070485).

21620405363 is a wasteful number, since it uses less digits than its factorization.

21620405363 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1070484.

The product of its (nonzero) digits is 25920, while the sum is 32.

Adding to 21620405363 its reverse (36350402612), we get a palindrome (57970807975).

The spelling of 21620405363 in words is "twenty-one billion, six hundred twenty million, four hundred five thousand, three hundred sixty-three".