1023999989 has 2 divisors, whose sum is σ = 1023999990. Its totient is φ = 1023999988.

The previous prime is 1023999961. The next prime is 1024000009. The reversal of 1023999989 is 9899993201.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 774675889 + 249324100 = 27833^2 + 15790^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1023999989 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1023999289) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 511999994 + 511999995.

It is an arithmetic number, because the mean of its divisors is an integer number (511999995).

Almost surely, 2^1023999989 is an apocalyptic number.

It is an amenable number.

1023999989 is a deficient number, since it is larger than the sum of its proper divisors (1).

1023999989 is an equidigital number, since it uses as much as digits as its factorization.

1023999989 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2834352, while the sum is 59.

The square root of 1023999989 is about 31999.9998281250. Note that the first 3 decimals coincide. The cubic root of 1023999989 is about 1007.9368363067.

The spelling of 1023999989 in words is "one billion, twenty-three million, nine hundred ninety-nine thousand, nine hundred eighty-nine".