20635631 has 2 divisors, whose sum is σ = 20635632. Its totient is φ = 20635630.

The previous prime is 20635627. The next prime is 20635633. The reversal of 20635631 is 13653602.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20635631 - 2² = 20635627 is a prime.

It is a super-2 number, since 2×20635631² = 851658533536322, which contains 22 as substring.

Together with 20635633, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20635631.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20635633) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10317815 + 10317816.

It is an arithmetic number, because the mean of its divisors is an integer number (10317816).

Almost surely, 2^20635631 is an apocalyptic number.

20635631 is a deficient number, since it is larger than the sum of its proper divisors (1).

20635631 is an equidigital number, since it uses as much as digits as its factorization.

20635631 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3240, while the sum is 26.

The square root of 20635631 is about 4542.6458149409. The cubic root of 20635631 is about 274.2874378948.

The spelling of 20635631 in words is "twenty million, six hundred thirty-five thousand, six hundred thirty-one".