21621266254605 has 8 divisors (see below), whose sum is σ = 34594026007392. Its totient is φ = 11531342002448.

The previous prime is 21621266254603. The next prime is 21621266254691. The reversal of 21621266254605 is 50645266212612.

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 21621266254605 - 2¹ = 21621266254603 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21621266254603) 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, 720708875139 + ... + 720708875168.

It is an arithmetic number, because the mean of its divisors is an integer number (4324253250924).

Almost surely, 2^{21621266254605} is an apocalyptic number.

It is an amenable number.

21621266254605 is a deficient number, since it is larger than the sum of its proper divisors (12972759752787).

21621266254605 is a wasteful number, since it uses less digits than its factorization.

21621266254605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1441417750315.

The product of its (nonzero) digits is 2073600, while the sum is 48.

The spelling of 21621266254605 in words is "twenty-one trillion, six hundred twenty-one billion, two hundred sixty-six million, two hundred fifty-four thousand, six hundred five".