23509440 has 140 divisors (see below), whose sum is σ = 83719416. Its totient is φ = 6262272.

The previous prime is 23509411. The next prime is 23509469. The reversal of 23509440 is 4490532.

It is an interprime number because it is at equal distance from previous prime (23509411) and next prime (23509469).

It is a super-2 number, since 2×23509440² = 1105387538227200, which contains 22 as substring.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 25467 + ... + 26373.

Almost surely, 2^23509440 is an apocalyptic number.

23509440 is a gapful number since it is divisible by the number (20) 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 23509440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41859708).

23509440 is an abundant number, since it is smaller than the sum of its proper divisors (60209976).

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

23509440 is an equidigital number, since it uses as much as digits as its factorization.

23509440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 936 (or 917 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 27.

The square root of 23509440 is about 4848.6534213119. The cubic root of 23509440 is about 286.4710642085.

Adding to 23509440 its reverse (4490532), we get a palindrome (27999972).

The spelling of 23509440 in words is "twenty-three million, five hundred nine thousand, four hundred forty".