90215987 has 2 divisors, whose sum is σ = 90215988. Its totient is φ = 90215986.

The previous prime is 90215977. The next prime is 90216001. The reversal of 90215987 is 78951209.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 90215987 - 2¹⁰ = 90214963 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (90215977) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45107993 + 45107994.

It is an arithmetic number, because the mean of its divisors is an integer number (45107994).

Almost surely, 2^90215987 is an apocalyptic number.

90215987 is a deficient number, since it is larger than the sum of its proper divisors (1).

90215987 is an equidigital number, since it uses as much as digits as its factorization.

90215987 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 45360, while the sum is 41.

The square root of 90215987 is about 9498.2096734069. The cubic root of 90215987 is about 448.4986790647.

Adding to 90215987 its sum of digits (41), we get a triangular number (90216028 = T₁₃₄₃₂).

The spelling of 90215987 in words is "ninety million, two hundred fifteen thousand, nine hundred eighty-seven".