1994257633 has 2 divisors, whose sum is σ = 1994257634. Its totient is φ = 1994257632.

The previous prime is 1994257631. The next prime is 1994257649. The reversal of 1994257633 is 3367524991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1799710929 + 194546704 = 42423^2 + 13948^2 .

It is an emirp because it is prime and its reverse (3367524991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1994257633 - 2¹ = 1994257631 is a prime.

Together with 1994257631, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (1994257631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 997128816 + 997128817.

It is an arithmetic number, because the mean of its divisors is an integer number (997128817).

Almost surely, 2^1994257633 is an apocalyptic number.

It is an amenable number.

1994257633 is a deficient number, since it is larger than the sum of its proper divisors (1).

1994257633 is an equidigital number, since it uses as much as digits as its factorization.

1994257633 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1224720, while the sum is 49.

The square root of 1994257633 is about 44657.1117852465. Note that the first 3 decimals coincide. The cubic root of 1994257633 is about 1258.7140724957.

The spelling of 1994257633 in words is "one billion, nine hundred ninety-four million, two hundred fifty-seven thousand, six hundred thirty-three".