21935393897 has 4 divisors (see below), whose sum is σ = 22691786820. Its totient is φ = 21179000976.

The previous prime is 21935393891. The next prime is 21935393911. The reversal of 21935393897 is 79839353912.

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 10142302681 + 11793091216 = 100709^2 + 108596^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21935393897 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21935393891) 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, 378196418 + ... + 378196475.

It is an arithmetic number, because the mean of its divisors is an integer number (5672946705).

Almost surely, 2^21935393897 is an apocalyptic number.

It is an amenable number.

21935393897 is a deficient number, since it is larger than the sum of its proper divisors (756392923).

21935393897 is an equidigital number, since it uses as much as digits as its factorization.

21935393897 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 756392922.

The product of its digits is 11022480, while the sum is 59.

The spelling of 21935393897 in words is "twenty-one billion, nine hundred thirty-five million, three hundred ninety-three thousand, eight hundred ninety-seven".