21557208541363 has 16 divisors (see below), whose sum is σ = 24540106311936. Its totient is φ = 18744882919840.

The previous prime is 21557208541357. The next prime is 21557208541391. The reversal of 21557208541363 is 36314580275512.

It is not a de Polignac number, because 21557208541363 - 2¹⁷ = 21557208410291 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21557208541363.

It is not an unprimeable number, because it can be changed into a prime (21557208541963) 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, 8187681 + ... + 10495357.

It is an arithmetic number, because the mean of its divisors is an integer number (1533756644496).

Almost surely, 2^{21557208541363} is an apocalyptic number.

21557208541363 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

21557208541363 is a deficient number, since it is larger than the sum of its proper divisors (2982897770573).

21557208541363 is a wasteful number, since it uses less digits than its factorization.

21557208541363 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2344634.

The product of its (nonzero) digits is 6048000, while the sum is 52.

The spelling of 21557208541363 in words is "twenty-one trillion, five hundred fifty-seven billion, two hundred eight million, five hundred forty-one thousand, three hundred sixty-three".