21010001099981 has 8 divisors (see below), whose sum is σ = 21423384612960. Its totient is φ = 20598526980432.

The previous prime is 21010001099957. The next prime is 21010001100017. The reversal of 21010001099981 is 18999010001012.

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 21010001099981 - 2⁶ = 21010001099917 is a prime.

It is a super-2 number, since 2×21010001099981² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21010001099951) 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, 477326135 + ... + 477370148.

It is an arithmetic number, because the mean of its divisors is an integer number (2677923076620).

Almost surely, 2^{21010001099981} is an apocalyptic number.

It is an amenable number.

21010001099981 is a deficient number, since it is larger than the sum of its proper divisors (413383512979).

21010001099981 is an equidigital number, since it uses as much as digits as its factorization.

21010001099981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 954696715.

The product of its (nonzero) digits is 11664, while the sum is 41.

The spelling of 21010001099981 in words is "twenty-one trillion, ten billion, one million, ninety-nine thousand, nine hundred eighty-one".