21091054057 has 8 divisors (see below), whose sum is σ = 21561111936. Its totient is φ = 20621884272.

The previous prime is 21091054043. The next prime is 21091054123. The reversal of 21091054057 is 75045019012.

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 21091054057 - 2¹¹ = 21091052009 is a prime.

It is a super-2 number, since 2×21091054057² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21091054007) 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, 173883 + ... + 269104.

It is an arithmetic number, because the mean of its divisors is an integer number (2695138992).

Almost surely, 2^21091054057 is an apocalyptic number.

It is an amenable number.

21091054057 is a deficient number, since it is larger than the sum of its proper divisors (470057879).

21091054057 is a wasteful number, since it uses less digits than its factorization.

21091054057 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 444047.

The product of its (nonzero) digits is 12600, while the sum is 34.

The spelling of 21091054057 in words is "twenty-one billion, ninety-one million, fifty-four thousand, fifty-seven".