21554215452051 has 16 divisors (see below), whose sum is σ = 28898194005408. Its totient is φ = 14289859468800.

The previous prime is 21554215452043. The next prime is 21554215452061. The reversal of 21554215452051 is 15025451245512.

It is not a de Polignac number, because 21554215452051 - 2³ = 21554215452043 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21554215451994 and 21554215452012.

It is not an unprimeable number, because it can be changed into a prime (21554215452061) 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, 37989585 + ... + 38552781.

It is an arithmetic number, because the mean of its divisors is an integer number (1806137125338).

Almost surely, 2^{21554215452051} is an apocalyptic number.

21554215452051 is a deficient number, since it is larger than the sum of its proper divisors (7343978553357).

21554215452051 is a wasteful number, since it uses less digits than its factorization.

21554215452051 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 633862.

The product of its (nonzero) digits is 400000, while the sum is 42.

Adding to 21554215452051 its reverse (15025451245512), we get a palindrome (36579666697563).

The spelling of 21554215452051 in words is "twenty-one trillion, five hundred fifty-four billion, two hundred fifteen million, four hundred fifty-two thousand, fifty-one".