21620551613305 has 16 divisors (see below), whose sum is σ = 26310430882944. Its totient is φ = 17052601829760.

The previous prime is 21620551613303. The next prime is 21620551613369. The reversal of 21620551613305 is 50331615502612.

It is a happy number.

It is not a de Polignac number, because 21620551613305 - 2¹ = 21620551613303 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21620551613303) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 29276734 + ... + 30006136.

It is an arithmetic number, because the mean of its divisors is an integer number (1644401930184).

Almost surely, 2^{21620551613305} is an apocalyptic number.

It is an amenable number.

21620551613305 is a deficient number, since it is larger than the sum of its proper divisors (4689879269639).

21620551613305 is an equidigital number, since it uses as much as digits as its factorization.

21620551613305 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 812976.

The product of its (nonzero) digits is 162000, while the sum is 40.

The spelling of 21620551613305 in words is "twenty-one trillion, six hundred twenty billion, five hundred fifty-one million, six hundred thirteen thousand, three hundred five".