21653051446621 has 4 divisors (see below), whose sum is σ = 24746344510432. Its totient is φ = 18559758382812.

The previous prime is 21653051446603. The next prime is 21653051446661. The reversal of 21653051446621 is 12664415035612.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21653051446621 - 2³⁵ = 21618691708253 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21653051446661) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1546646531895 + ... + 1546646531908.

It is an arithmetic number, because the mean of its divisors is an integer number (6186586127608).

Almost surely, 2^{21653051446621} is an apocalyptic number.

It is an amenable number.

21653051446621 is a deficient number, since it is larger than the sum of its proper divisors (3093293063811).

21653051446621 is an equidigital number, since it uses as much as digits as its factorization.

21653051446621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3093293063810.

The product of its (nonzero) digits is 1036800, while the sum is 46.

The spelling of 21653051446621 in words is "twenty-one trillion, six hundred fifty-three billion, fifty-one million, four hundred forty-six thousand, six hundred twenty-one".