90991887 has 16 divisors (see below), whose sum is σ = 144683520. Its totient is φ = 49734432.

The previous prime is 90991883. The next prime is 90991889. The reversal of 90991887 is 78819909.

It is not a de Polignac number, because 90991887 - 2² = 90991883 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (90991883) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 93712 + ... + 94677.

It is an arithmetic number, because the mean of its divisors is an integer number (9042720).

Almost surely, 2^90991887 is an apocalyptic number.

90991887 is a deficient number, since it is larger than the sum of its proper divisors (53691633).

90991887 is a wasteful number, since it uses less digits than its factorization.

90991887 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 188422.

The product of its (nonzero) digits is 326592, while the sum is 51.

The square root of 90991887 is about 9538.9667679471. The cubic root of 90991887 is about 449.7807771710.

The spelling of 90991887 in words is "ninety million, nine hundred ninety-one thousand, eight hundred eighty-seven".