21155333621431 has 8 divisors (see below), whose sum is σ = 21272450929184. Its totient is φ = 21038218918560.

The previous prime is 21155333621377. The next prime is 21155333621467. The reversal of 21155333621431 is 13412633355112.

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 21155333621431 - 2¹⁷ = 21155333490359 is a prime.

It is a super-2 number, since 2×21155333621431² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21155333621531) 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, 16949470 + ... + 18154756.

It is an arithmetic number, because the mean of its divisors is an integer number (2659056366148).

Almost surely, 2^{21155333621431} is an apocalyptic number.

21155333621431 is a deficient number, since it is larger than the sum of its proper divisors (117117307753).

21155333621431 is a wasteful number, since it uses less digits than its factorization.

21155333621431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1302441.

The product of its digits is 194400, while the sum is 40.

Adding to 21155333621431 its reverse (13412633355112), we get a palindrome (34567966976543).

The spelling of 21155333621431 in words is "twenty-one trillion, one hundred fifty-five billion, three hundred thirty-three million, six hundred twenty-one thousand, four hundred thirty-one".