23206640 has 20 divisors (see below), whose sum is σ = 53955624. Its totient is φ = 9282624.

The previous prime is 23206639. The next prime is 23206643. The reversal of 23206640 is 4660232.

It is a tau number, because it is divible by the number of its divisors (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (23206643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 144962 + ... + 145121.

Almost surely, 2^23206640 is an apocalyptic number.

23206640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

23206640 is an abundant number, since it is smaller than the sum of its proper divisors (30748984).

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

23206640 is a wasteful number, since it uses less digits than its factorization.

23206640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 290096 (or 290090 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 23.

The square root of 23206640 is about 4817.3270596878. The cubic root of 23206640 is about 285.2358363919.

Adding to 23206640 its reverse (4660232), we get a palindrome (27866872).

The spelling of 23206640 in words is "twenty-three million, two hundred six thousand, six hundred forty".