21741631 has 2 divisors, whose sum is σ = 21741632. Its totient is φ = 21741630.

The previous prime is 21741613. The next prime is 21741641. The reversal of 21741631 is 13614712.

Together with previous prime (21741613) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21741631 - 2²¹ = 19644479 is a prime.

It is a super-2 number, since 2×21741631² = 945397037080322, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21741596 and 21741605.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21741641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10870815 + 10870816.

It is an arithmetic number, because the mean of its divisors is an integer number (10870816).

Almost surely, 2^21741631 is an apocalyptic number.

21741631 is a deficient number, since it is larger than the sum of its proper divisors (1).

21741631 is an equidigital number, since it uses as much as digits as its factorization.

21741631 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1008, while the sum is 25.

The square root of 21741631 is about 4662.7921892360. The cubic root of 21741631 is about 279.1027015351.

The spelling of 21741631 in words is "twenty-one million, seven hundred forty-one thousand, six hundred thirty-one".