21661042100506 has 8 divisors (see below), whose sum is σ = 32521454196480. Its totient is φ = 10820557368348.

The previous prime is 21661042100501. The next prime is 21661042100527. The reversal of 21661042100506 is 60500124016612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (21661042100501) 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, 4981838236 + ... + 4981842583.

It is an arithmetic number, because the mean of its divisors is an integer number (4065181774560).

Almost surely, 2^{21661042100506} is an apocalyptic number.

21661042100506 is a deficient number, since it is larger than the sum of its proper divisors (10860412095974).

21661042100506 is a wasteful number, since it uses less digits than its factorization.

21661042100506 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9963681908.

The product of its (nonzero) digits is 17280, while the sum is 34.

The spelling of 21661042100506 in words is "twenty-one trillion, six hundred sixty-one billion, forty-two million, one hundred thousand, five hundred six".