21155532121356 has 24 divisors (see below), whose sum is σ = 49378426419504. Its totient is φ = 7049627163840.

The previous prime is 21155532121327. The next prime is 21155532121363. The reversal of 21155532121356 is 65312123555112.

It is a super-2 number, since 2×21155532121356² (a number of 27 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 277069815 + ... + 277146158.

It is an arithmetic number, because the mean of its divisors is an integer number (2057434434146).

Almost surely, 2^{21155532121356} is an apocalyptic number.

It is an amenable number.

21155532121356 is an abundant number, since it is smaller than the sum of its proper divisors (28222894298148).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21155532121356 is a wasteful number, since it uses less digits than its factorization.

21155532121356 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 554219161 (or 554219159 counting only the distinct ones).

The product of its digits is 270000, while the sum is 42.

Adding to 21155532121356 its reverse (65312123555112), we get a palindrome (86467655676468).

The spelling of 21155532121356 in words is "twenty-one trillion, one hundred fifty-five billion, five hundred thirty-two million, one hundred twenty-one thousand, three hundred fifty-six".