919987231 has 2 divisors, whose sum is σ = 919987232. Its totient is φ = 919987230.

The previous prime is 919987223. The next prime is 919987247. The reversal of 919987231 is 132789919.

It is a weak prime.

It is an emirp because it is prime and its reverse (132789919) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 919987231 - 2³ = 919987223 is a prime.

It is a super-2 number, since 2×919987231² = 1692753010406094722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (919987261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 459993615 + 459993616.

It is an arithmetic number, because the mean of its divisors is an integer number (459993616).

Almost surely, 2^919987231 is an apocalyptic number.

919987231 is a deficient number, since it is larger than the sum of its proper divisors (1).

919987231 is an equidigital number, since it uses as much as digits as its factorization.

919987231 is an evil number, because the sum of its binary digits is even.

The product of its digits is 244944, while the sum is 49.

The square root of 919987231 is about 30331.2912847442. The cubic root of 919987231 is about 972.5843265652.

The spelling of 919987231 in words is "nine hundred nineteen million, nine hundred eighty-seven thousand, two hundred thirty-one".