21653040640263 has 16 divisors (see below), whose sum is σ = 28954094400480. Its totient is φ = 14393678137344.

The previous prime is 21653040640241. The next prime is 21653040640267. The reversal of 21653040640263 is 36204604035612.

It is a happy number.

It is not a de Polignac number, because 21653040640263 - 2²⁴ = 21653023863047 is a prime.

It is a super-2 number, since 2×21653040640263² (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 (21653040640267) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19096593 + ... + 20198661.

It is an arithmetic number, because the mean of its divisors is an integer number (1809630900030).

Almost surely, 2^{21653040640263} is an apocalyptic number.

21653040640263 is a deficient number, since it is larger than the sum of its proper divisors (7301053760217).

21653040640263 is a wasteful number, since it uses less digits than its factorization.

21653040640263 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1120978.

The product of its (nonzero) digits is 622080, while the sum is 42.

Adding to 21653040640263 its reverse (36204604035612), we get a palindrome (57857644675875).

The spelling of 21653040640263 in words is "twenty-one trillion, six hundred fifty-three billion, forty million, six hundred forty thousand, two hundred sixty-three".