73121020021 has 4 divisors (see below), whose sum is σ = 83566880032. Its totient is φ = 62675160012.

The previous prime is 73121019997. The next prime is 73121020039. The reversal of 73121020021 is 12002012137.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 73121020021 - 2³³ = 64531085429 is a prime.

It is a super-2 number, since 2×73121020021² (a number of 23 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 (73121020081) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5222929995 + ... + 5222930008.

It is an arithmetic number, because the mean of its divisors is an integer number (20891720008).

Almost surely, 2^73121020021 is an apocalyptic number.

It is an amenable number.

73121020021 is a deficient number, since it is larger than the sum of its proper divisors (10445860011).

73121020021 is a wasteful number, since it uses less digits than its factorization.

73121020021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10445860010.

The product of its (nonzero) digits is 168, while the sum is 19.

Adding to 73121020021 its reverse (12002012137), we get a palindrome (85123032158).

The spelling of 73121020021 in words is "seventy-three billion, one hundred twenty-one million, twenty thousand, twenty-one".