90243720 has 320 divisors, whose sum is σ = 363813120. Its totient is φ = 19616256.

The previous prime is 90243709. The next prime is 90243731. The reversal of 90243720 is 2734209.

It is an interprime number because it is at equal distance from previous prime (90243709) and next prime (90243731).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 521554 + ... + 521726.

It is an arithmetic number, because the mean of its divisors is an integer number (1136916).

Almost surely, 2^90243720 is an apocalyptic number.

90243720 is a gapful number since it is divisible by the number (90) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 90243720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (181906560).

90243720 is an abundant number, since it is smaller than the sum of its proper divisors (273569400).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

90243720 is a wasteful number, since it uses less digits than its factorization.

90243720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 226 (or 213 counting only the distinct ones).

The product of its (nonzero) digits is 3024, while the sum is 27.

The square root of 90243720 is about 9499.6694679341. The cubic root of 90243720 is about 448.5446315245.

Adding to 90243720 its reverse (2734209), we get a palindrome (92977929).

The spelling of 90243720 in words is "ninety million, two hundred forty-three thousand, seven hundred twenty".