21701837 has 2 divisors, whose sum is σ = 21701838. Its totient is φ = 21701836.

The previous prime is 21701821. The next prime is 21701839. The reversal of 21701837 is 73810712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17147881 + 4553956 = 4141^2 + 2134^2 .

It is a cyclic number.

It is not a de Polignac number, because 21701837 - 2⁴ = 21701821 is a prime.

Together with 21701839, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21701839) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10850918 + 10850919.

It is an arithmetic number, because the mean of its divisors is an integer number (10850919).

Almost surely, 2^21701837 is an apocalyptic number.

It is an amenable number.

21701837 is a deficient number, since it is larger than the sum of its proper divisors (1).

21701837 is an equidigital number, since it uses as much as digits as its factorization.

21701837 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2352, while the sum is 29.

The square root of 21701837 is about 4658.5230492078. The cubic root of 21701837 is about 278.9323157286.

The spelling of 21701837 in words is "twenty-one million, seven hundred one thousand, eight hundred thirty-seven".