21102021010981 has 2 divisors, whose sum is σ = 21102021010982. Its totient is φ = 21102021010980.

The previous prime is 21102021010969. The next prime is 21102021011069. The reversal of 21102021010981 is 18901012020112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18866296296225 + 2235724714756 = 4343535^2 + 1495234^2 .

It is a cyclic number.

It is not a de Polignac number, because 21102021010981 - 2²³ = 21102012622373 is a prime.

It is a super-2 number, since 2×21102021010981² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (22102021010981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10551010505490 + 10551010505491.

It is an arithmetic number, because the mean of its divisors is an integer number (10551010505491).

Almost surely, 2^{21102021010981} is an apocalyptic number.

It is an amenable number.

21102021010981 is a deficient number, since it is larger than the sum of its proper divisors (1).

21102021010981 is an equidigital number, since it uses as much as digits as its factorization.

21102021010981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 576, while the sum is 28.

The spelling of 21102021010981 in words is "twenty-one trillion, one hundred two billion, twenty-one million, ten thousand, nine hundred eighty-one".