20631869 has 2 divisors, whose sum is σ = 20631870. Its totient is φ = 20631868.

The previous prime is 20631857. The next prime is 20631899. The reversal of 20631869 is 96813602.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11256025 + 9375844 = 3355^2 + 3062^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20631869 is a prime.

It is a super-2 number, since 2×20631869² = 851348036866322, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20631899) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10315934 + 10315935.

It is an arithmetic number, because the mean of its divisors is an integer number (10315935).

Almost surely, 2^20631869 is an apocalyptic number.

It is an amenable number.

20631869 is a deficient number, since it is larger than the sum of its proper divisors (1).

20631869 is an equidigital number, since it uses as much as digits as its factorization.

20631869 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 15552, while the sum is 35.

The square root of 20631869 is about 4542.2317202010. The cubic root of 20631869 is about 274.2707687970.

The spelling of 20631869 in words is "twenty million, six hundred thirty-one thousand, eight hundred sixty-nine".