21616055001 has 12 divisors (see below), whose sum is σ = 31227153828. Its totient is φ = 14408874144.

The previous prime is 21616054997. The next prime is 21616055023. The reversal of 21616055001 is 10055061612.

It is a happy number.

21616055001 is a `hidden beast` number, since 2 + 1 + 6 + 1 + 605 + 50 + 0 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 13069976976 + 8546078025 = 114324^2 + 92445^2 .

It is not a de Polignac number, because 21616055001 - 2² = 21616054997 is a prime.

It is a super-2 number, since 2×21616055001² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21616055801) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 75550 + ... + 221223.

It is an arithmetic number, because the mean of its divisors is an integer number (2602262819).

Almost surely, 2^21616055001 is an apocalyptic number.

It is an amenable number.

21616055001 is a deficient number, since it is larger than the sum of its proper divisors (9611098827).

21616055001 is a wasteful number, since it uses less digits than its factorization.

21616055001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 304872 (or 304869 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 27.

The spelling of 21616055001 in words is "twenty-one billion, six hundred sixteen million, fifty-five thousand, one".