21661020530641 has 32 divisors (see below), whose sum is σ = 24325118812800. Its totient is φ = 19167945753600.

The previous prime is 21661020530627. The next prime is 21661020530683. The reversal of 21661020530641 is 14603502016612.

It is not a de Polignac number, because 21661020530641 - 2³⁹ = 21111264716753 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21661020530641.

It is not an unprimeable number, because it can be changed into a prime (21661020530041) 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, 36613495 + ... + 37200403.

It is an arithmetic number, because the mean of its divisors is an integer number (760159962900).

Almost surely, 2^{21661020530641} is an apocalyptic number.

It is an amenable number.

21661020530641 is a deficient number, since it is larger than the sum of its proper divisors (2664098282159).

21661020530641 is a wasteful number, since it uses less digits than its factorization.

21661020530641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 587809.

The product of its (nonzero) digits is 51840, while the sum is 37.

The spelling of 21661020530641 in words is "twenty-one trillion, six hundred sixty-one billion, twenty million, five hundred thirty thousand, six hundred forty-one".