21900937 has 2 divisors, whose sum is σ = 21900938. Its totient is φ = 21900936.

The previous prime is 21900883. The next prime is 21900953. The reversal of 21900937 is 73900912.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20169081 + 1731856 = 4491^2 + 1316^2 .

It is a cyclic number.

It is not a de Polignac number, because 21900937 - 2¹¹ = 21898889 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21900899 and 21900908.

It is not a weakly prime, because it can be changed into another prime (21900997) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10950468 + 10950469.

It is an arithmetic number, because the mean of its divisors is an integer number (10950469).

Almost surely, 2^21900937 is an apocalyptic number.

It is an amenable number.

21900937 is a deficient number, since it is larger than the sum of its proper divisors (1).

21900937 is an equidigital number, since it uses as much as digits as its factorization.

21900937 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3402, while the sum is 31.

The square root of 21900937 is about 4679.8436939710. The cubic root of 21900937 is about 279.7827268531.

The spelling of 21900937 in words is "twenty-one million, nine hundred thousand, nine hundred thirty-seven".