90243661 has 4 divisors (see below), whose sum is σ = 90268192. Its totient is φ = 90219132.

The previous prime is 90243649. The next prime is 90243689. The reversal of 90243661 is 16634209.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 16634209 = 53 ⋅313853.

It is a cyclic number.

It is not a de Polignac number, because 90243661 - 2¹³ = 90235469 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (90243611) 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, 5505 + ... + 14518.

It is an arithmetic number, because the mean of its divisors is an integer number (22567048).

Almost surely, 2^90243661 is an apocalyptic number.

It is an amenable number.

90243661 is a deficient number, since it is larger than the sum of its proper divisors (24531).

90243661 is a wasteful number, since it uses less digits than its factorization.

90243661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24530.

The product of its (nonzero) digits is 7776, while the sum is 31.

The square root of 90243661 is about 9499.6663625624. Note that the first 3 decimals coincide. The cubic root of 90243661 is about 448.5445337739.

The spelling of 90243661 in words is "ninety million, two hundred forty-three thousand, six hundred sixty-one".