21092101921 has 8 divisors (see below), whose sum is σ = 23011916544. Its totient is φ = 19172679120.

The previous prime is 21092101903. The next prime is 21092101937. The reversal of 21092101921 is 12910129012.

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

It is a cyclic number.

It is not a de Polignac number, because 21092101921 - 2⁵ = 21092101889 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21092101921.

It is not an unprimeable number, because it can be changed into a prime (21092101021) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20880 + ... + 206446.

It is an arithmetic number, because the mean of its divisors is an integer number (2876489568).

Almost surely, 2^21092101921 is an apocalyptic number.

It is an amenable number.

21092101921 is a deficient number, since it is larger than the sum of its proper divisors (1919814623).

21092101921 is a wasteful number, since it uses less digits than its factorization.

21092101921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 195911.

The product of its (nonzero) digits is 648, while the sum is 28.

The spelling of 21092101921 in words is "twenty-one billion, ninety-two million, one hundred one thousand, nine hundred twenty-one".