21894737 has 2 divisors, whose sum is σ = 21894738. Its totient is φ = 21894736.

The previous prime is 21894703. The next prime is 21894751. The reversal of 21894737 is 73749812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19018321 + 2876416 = 4361^2 + 1696^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21894737 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21894694 and 21894703.

It is not a weakly prime, because it can be changed into another prime (21804737) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10947368 + 10947369.

It is an arithmetic number, because the mean of its divisors is an integer number (10947369).

Almost surely, 2^21894737 is an apocalyptic number.

It is an amenable number.

21894737 is a deficient number, since it is larger than the sum of its proper divisors (1).

21894737 is an equidigital number, since it uses as much as digits as its factorization.

21894737 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 84672, while the sum is 41.

The square root of 21894737 is about 4679.1812317969. The cubic root of 21894737 is about 279.7563228592.

The spelling of 21894737 in words is "twenty-one million, eight hundred ninety-four thousand, seven hundred thirty-seven".