21502544051055 has 32 divisors (see below), whose sum is σ = 36461352075264. Its totient is φ = 10783504175616.

The previous prime is 21502544051017. The next prime is 21502544051057. The reversal of 21502544051055 is 55015044520512.

It is a happy number.

It is not a de Polignac number, because 21502544051055 - 2⁹ = 21502544050543 is a prime.

It is a super-2 number, since 2×21502544051055² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21502544051057) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 38510167 + ... + 39064536.

It is an arithmetic number, because the mean of its divisors is an integer number (1139417252352).

Almost surely, 2^{21502544051055} is an apocalyptic number.

21502544051055 is a deficient number, since it is larger than the sum of its proper divisors (14958808024209).

21502544051055 is a wasteful number, since it uses less digits than its factorization.

21502544051055 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77575815.

The product of its (nonzero) digits is 200000, while the sum is 39.

Adding to 21502544051055 its reverse (55015044520512), we get a palindrome (76517588571567).

The spelling of 21502544051055 in words is "twenty-one trillion, five hundred two billion, five hundred forty-four million, fifty-one thousand, fifty-five".