221121979493 has 2 divisors, whose sum is σ = 221121979494. Its totient is φ = 221121979492.

The previous prime is 221121979487. The next prime is 221121979541. The reversal of 221121979493 is 394979121122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 152082840484 + 69039139009 = 389978^2 + 262753^2 .

It is a cyclic number.

It is not a de Polignac number, because 221121979493 - 2⁸ = 221121979237 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221121979433) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110560989746 + 110560989747.

It is an arithmetic number, because the mean of its divisors is an integer number (110560989747).

Almost surely, 2^221121979493 is an apocalyptic number.

It is an amenable number.

221121979493 is a deficient number, since it is larger than the sum of its proper divisors (1).

221121979493 is an equidigital number, since it uses as much as digits as its factorization.

221121979493 is an evil number, because the sum of its binary digits is even.

The product of its digits is 489888, while the sum is 50.

The spelling of 221121979493 in words is "two hundred twenty-one billion, one hundred twenty-one million, nine hundred seventy-nine thousand, four hundred ninety-three".