720919987 has 2 divisors, whose sum is σ = 720919988. Its totient is φ = 720919986.

The previous prime is 720919967. The next prime is 720920009. The reversal of 720919987 is 789919027.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-720919987 is a prime.

It is not a weakly prime, because it can be changed into another prime (720919967) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360459993 + 360459994.

It is an arithmetic number, because the mean of its divisors is an integer number (360459994).

Almost surely, 2^720919987 is an apocalyptic number.

720919987 is a deficient number, since it is larger than the sum of its proper divisors (1).

720919987 is an equidigital number, since it uses as much as digits as its factorization.

720919987 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 571536, while the sum is 52.

The square root of 720919987 is about 26849.9532029387. The cubic root of 720919987 is about 896.6625307334.

The spelling of 720919987 in words is "seven hundred twenty million, nine hundred nineteen thousand, nine hundred eighty-seven".