21548855638081 has 4 divisors (see below), whose sum is σ = 21551232271792. Its totient is φ = 21546479004372.

The previous prime is 21548855638049. The next prime is 21548855638091. The reversal of 21548855638081 is 18083655884512.

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 21548855638081 - 2⁵ = 21548855638049 is a prime.

It is a super-2 number, since 2×21548855638081² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21548855638091) 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, 1188303255 + ... + 1188321388.

It is an arithmetic number, because the mean of its divisors is an integer number (5387808067948).

Almost surely, 2^{21548855638081} is an apocalyptic number.

It is an amenable number.

21548855638081 is a deficient number, since it is larger than the sum of its proper divisors (2376633711).

21548855638081 is an equidigital number, since it uses as much as digits as its factorization.

21548855638081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2376633710.

The product of its (nonzero) digits is 73728000, while the sum is 64.

The spelling of 21548855638081 in words is "twenty-one trillion, five hundred forty-eight billion, eight hundred fifty-five million, six hundred thirty-eight thousand, eighty-one".