21799937 has 2 divisors, whose sum is σ = 21799938. Its totient is φ = 21799936.

The previous prime is 21799901. The next prime is 21799979. The reversal of 21799937 is 73999712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15241216 + 6558721 = 3904^2 + 2561^2 .

It is a cyclic number.

It is not a de Polignac number, because 21799937 - 2²⁰ = 20751361 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21799891 and 21799900.

It is not a weakly prime, because it can be changed into another prime (21709937) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10899968 + 10899969.

It is an arithmetic number, because the mean of its divisors is an integer number (10899969).

Almost surely, 2^21799937 is an apocalyptic number.

It is an amenable number.

21799937 is a deficient number, since it is larger than the sum of its proper divisors (1).

21799937 is an equidigital number, since it uses as much as digits as its factorization.

21799937 is an evil number, because the sum of its binary digits is even.

The product of its digits is 214326, while the sum is 47.

The square root of 21799937 is about 4669.0402654079. The cubic root of 21799937 is about 279.3519750237.

The spelling of 21799937 in words is "twenty-one million, seven hundred ninety-nine thousand, nine hundred thirty-seven".