21520722267563 has 4 divisors (see below), whose sum is σ = 21582741640440. Its totient is φ = 21458702894688.

The previous prime is 21520722267559. The next prime is 21520722267581. The reversal of 21520722267563 is 36576222702512.

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 21520722267563 - 2² = 21520722267559 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21520722267503) 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, 31009685918 + ... + 31009686611.

It is an arithmetic number, because the mean of its divisors is an integer number (5395685410110).

Almost surely, 2^{21520722267563} is an apocalyptic number.

21520722267563 is a deficient number, since it is larger than the sum of its proper divisors (62019372877).

21520722267563 is an equidigital number, since it uses as much as digits as its factorization.

21520722267563 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62019372876.

The product of its (nonzero) digits is 4233600, while the sum is 50.

The spelling of 21520722267563 in words is "twenty-one trillion, five hundred twenty billion, seven hundred twenty-two million, two hundred sixty-seven thousand, five hundred sixty-three".