21661353005005 has 32 divisors (see below), whose sum is σ = 29788092949248. Its totient is φ = 14812976908800.

The previous prime is 21661353004999. The next prime is 21661353005027. The reversal of 21661353005005 is 50050035316612.

It is not a de Polignac number, because 21661353005005 - 2²¹ = 21661350907853 is a prime.

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 31 ways as a sum of consecutive naturals, for example, 41633065 + ... + 42150145.

It is an arithmetic number, because the mean of its divisors is an integer number (930877904664).

Almost surely, 2^{21661353005005} is an apocalyptic number.

It is an amenable number.

21661353005005 is a deficient number, since it is larger than the sum of its proper divisors (8126739944243).

21661353005005 is a wasteful number, since it uses less digits than its factorization.

21661353005005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 520357.

The product of its (nonzero) digits is 81000, while the sum is 37.

The spelling of 21661353005005 in words is "twenty-one trillion, six hundred sixty-one billion, three hundred fifty-three million, five thousand, five".