21930237997 has 4 divisors (see below), whose sum is σ = 21936173596. Its totient is φ = 21924302400.

The previous prime is 21930237943. The next prime is 21930238027. The reversal of 21930237997 is 79973203912.

It is a happy number.

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 5901158761 + 16029079236 = 76819^2 + 126606^2 .

It is a cyclic number.

It is not a de Polignac number, because 21930237997 - 2¹⁹ = 21929713709 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21930237907) 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, 2962254 + ... + 2969647.

It is an arithmetic number, because the mean of its divisors is an integer number (5484043399).

Almost surely, 2^21930237997 is an apocalyptic number.

It is an amenable number.

21930237997 is a deficient number, since it is larger than the sum of its proper divisors (5935599).

21930237997 is an equidigital number, since it uses as much as digits as its factorization.

21930237997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5935598.

The product of its (nonzero) digits is 1285956, while the sum is 52.

The spelling of 21930237997 in words is "twenty-one billion, nine hundred thirty million, two hundred thirty-seven thousand, nine hundred ninety-seven".