21012100210091 has 4 divisors (see below), whose sum is σ = 21012128166072. Its totient is φ = 21012072254112.

The previous prime is 21012100210033. The next prime is 21012100210109. The reversal of 21012100210091 is 19001200121012.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21012100210091 - 2²² = 21012096015787 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21012100210021) 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, 12818510 + ... + 14364483.

It is an arithmetic number, because the mean of its divisors is an integer number (5253032041518).

Almost surely, 2^{21012100210091} is an apocalyptic number.

21012100210091 is a deficient number, since it is larger than the sum of its proper divisors (27955981).

21012100210091 is an equidigital number, since it uses as much as digits as its factorization.

21012100210091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27955980.

The product of its (nonzero) digits is 72, while the sum is 20.

The spelling of 21012100210091 in words is "twenty-one trillion, twelve billion, one hundred million, two hundred ten thousand, ninety-one".