20631899 has 2 divisors, whose sum is σ = 20631900. Its totient is φ = 20631898.

The previous prime is 20631869. The next prime is 20631907. The reversal of 20631899 is 99813602.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20631899 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20631869) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10315949 + 10315950.

It is an arithmetic number, because the mean of its divisors is an integer number (10315950).

Almost surely, 2^20631899 is an apocalyptic number.

20631899 is a deficient number, since it is larger than the sum of its proper divisors (1).

20631899 is an equidigital number, since it uses as much as digits as its factorization.

20631899 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 23328, while the sum is 38.

The square root of 20631899 is about 4542.2350225412. The cubic root of 20631899 is about 274.2709017324.

The spelling of 20631899 in words is "twenty million, six hundred thirty-one thousand, eight hundred ninety-nine".