21131701 has 2 divisors, whose sum is σ = 21131702. Its totient is φ = 21131700.

The previous prime is 21131689. The next prime is 21131707. The reversal of 21131701 is 10713112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11737476 + 9394225 = 3426^2 + 3065^2 .

It is a cyclic number.

It is not a de Polignac number, because 21131701 - 2⁷ = 21131573 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21131707) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10565850 + 10565851.

It is an arithmetic number, because the mean of its divisors is an integer number (10565851).

Almost surely, 2^21131701 is an apocalyptic number.

It is an amenable number.

21131701 is a deficient number, since it is larger than the sum of its proper divisors (1).

21131701 is an equidigital number, since it uses as much as digits as its factorization.

21131701 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 42, while the sum is 16.

The square root of 21131701 is about 4596.9229926115. The cubic root of 21131701 is about 276.4679670377.

Adding to 21131701 its reverse (10713112), we get a palindrome (31844813).

The spelling of 21131701 in words is "twenty-one million, one hundred thirty-one thousand, seven hundred one".