90420987 has 4 divisors (see below), whose sum is σ = 120561320. Its totient is φ = 60280656.

The previous prime is 90420961. The next prime is 90420991. The reversal of 90420987 is 78902409.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 90420987 - 2¹² = 90416891 is a prime.

It is a super-3 number, since 3×90420987³ (a number of 25 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (90420907) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15070162 + ... + 15070167.

It is an arithmetic number, because the mean of its divisors is an integer number (30140330).

Almost surely, 2^90420987 is an apocalyptic number.

90420987 is a deficient number, since it is larger than the sum of its proper divisors (30140333).

90420987 is a wasteful number, since it uses less digits than its factorization.

90420987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30140332.

The product of its (nonzero) digits is 36288, while the sum is 39.

The square root of 90420987 is about 9508.9950573128. The cubic root of 90420987 is about 448.8381335937.

The spelling of 90420987 in words is "ninety million, four hundred twenty thousand, nine hundred eighty-seven".