21655225243531 has 8 divisors (see below), whose sum is σ = 23853240163584. Its totient is φ = 19495436670120.

The previous prime is 21655225243529. The next prime is 21655225243571. The reversal of 21655225243531 is 13534252255612.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21655225243531 - 2¹ = 21655225243529 is a prime.

It is a super-2 number, since 2×21655225243531² (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 (21655225243571) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9556585471 + ... + 9556587736.

It is an arithmetic number, because the mean of its divisors is an integer number (2981655020448).

Almost surely, 2^{21655225243531} is an apocalyptic number.

21655225243531 is a deficient number, since it is larger than the sum of its proper divisors (2198014920053).

21655225243531 is a wasteful number, since it uses less digits than its factorization.

21655225243531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19113173321.

The product of its digits is 2160000, while the sum is 46.

The spelling of 21655225243531 in words is "twenty-one trillion, six hundred fifty-five billion, two hundred twenty-five million, two hundred forty-three thousand, five hundred thirty-one".