21256727099 has 8 divisors (see below), whose sum is σ = 21344428560. Its totient is φ = 21169105056.

The previous prime is 21256727059. The next prime is 21256727123. The reversal of 21256727099 is 99072765212.

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 21256727099 - 2¹⁶ = 21256661563 is a prime.

It is a super-2 number, since 2×21256727099² (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 (21256727039) 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, 549992 + ... + 587370.

It is an arithmetic number, because the mean of its divisors is an integer number (2668053570).

Almost surely, 2^21256727099 is an apocalyptic number.

21256727099 is a deficient number, since it is larger than the sum of its proper divisors (87701461).

21256727099 is a wasteful number, since it uses less digits than its factorization.

21256727099 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39709.

The product of its (nonzero) digits is 952560, while the sum is 50.

The spelling of 21256727099 in words is "twenty-one billion, two hundred fifty-six million, seven hundred twenty-seven thousand, ninety-nine".