633942989 has 2 divisors, whose sum is σ = 633942990. Its totient is φ = 633942988.

The previous prime is 633942931. The next prime is 633943033. The reversal of 633942989 is 989249336.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 605406025 + 28536964 = 24605^2 + 5342^2 .

It is a cyclic number.

It is not a de Polignac number, because 633942989 - 2²⁸ = 365507533 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 633942989.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (633944989) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 316971494 + 316971495.

It is an arithmetic number, because the mean of its divisors is an integer number (316971495).

Almost surely, 2^633942989 is an apocalyptic number.

It is an amenable number.

633942989 is a deficient number, since it is larger than the sum of its proper divisors (1).

633942989 is an equidigital number, since it uses as much as digits as its factorization.

633942989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2519424, while the sum is 53.

The square root of 633942989 is about 25178.2245005481. The cubic root of 633942989 is about 859.0466219704.

The spelling of 633942989 in words is "six hundred thirty-three million, nine hundred forty-two thousand, nine hundred eighty-nine".