21663012343655 has 16 divisors (see below), whose sum is σ = 26173781091264. Its totient is φ = 17211685075200.

The previous prime is 21663012343649. The next prime is 21663012343711. The reversal of 21663012343655 is 55634321036612.

It is not a de Polignac number, because 21663012343655 - 2²⁴ = 21662995566439 is a prime.

It is a super-2 number, since 2×21663012343655² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3182 + ... + 6582251.

It is an arithmetic number, because the mean of its divisors is an integer number (1635861318204).

Almost surely, 2^{21663012343655} is an apocalyptic number.

21663012343655 is a deficient number, since it is larger than the sum of its proper divisors (4510768747609).

21663012343655 is a wasteful number, since it uses less digits than its factorization.

21663012343655 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6589946.

The product of its (nonzero) digits is 2332800, while the sum is 47.

The spelling of 21663012343655 in words is "twenty-one trillion, six hundred sixty-three billion, twelve million, three hundred forty-three thousand, six hundred fifty-five".