91021202002021 has 4 divisors (see below), whose sum is σ = 91127411106732. Its totient is φ = 90914992897312.

The previous prime is 91021202002019. The next prime is 91021202002039. The reversal of 91021202002021 is 12020020212019.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 45726821389921 + 45294380612100 = 6762161^2 + 6730110^2 .

It is a cyclic number.

It is not a de Polignac number, because 91021202002021 - 2¹ = 91021202002019 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 91021202001983 and 91021202002001.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91021202002051) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 53104551070 + ... + 53104552783.

It is an arithmetic number, because the mean of its divisors is an integer number (22781852776683).

Almost surely, 2^{91021202002021} is an apocalyptic number.

It is an amenable number.

91021202002021 is a deficient number, since it is larger than the sum of its proper divisors (106209104711).

91021202002021 is a wasteful number, since it uses less digits than its factorization.

91021202002021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 106209104710.

The product of its (nonzero) digits is 288, while the sum is 22.

The spelling of 91021202002021 in words is "ninety-one trillion, twenty-one billion, two hundred two million, two thousand, twenty-one".