21663021501231 has 32 divisors (see below), whose sum is σ = 32665894410240. Its totient is φ = 12651053913600.

The previous prime is 21663021501179. The next prime is 21663021501257. The reversal of 21663021501231 is 13210512036612.

It is not a de Polignac number, because 21663021501231 - 2¹⁴ = 21663021484847 is a prime.

It is a super-2 number, since 2×21663021501231² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a junction number, because it is equal to n+sod(n) for n = 21663021501192 and 21663021501201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21663021301231) 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, 45203646 + ... + 45680363.

It is an arithmetic number, because the mean of its divisors is an integer number (1020809200320).

Almost surely, 2^{21663021501231} is an apocalyptic number.

21663021501231 is a deficient number, since it is larger than the sum of its proper divisors (11002872909009).

21663021501231 is a wasteful number, since it uses less digits than its factorization.

21663021501231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90884287.

The product of its (nonzero) digits is 12960, while the sum is 33.

Adding to 21663021501231 its reverse (13210512036612), we get a palindrome (34873533537843).

The spelling of 21663021501231 in words is "twenty-one trillion, six hundred sixty-three billion, twenty-one million, five hundred one thousand, two hundred thirty-one".