20613240 has 48 divisors (see below), whose sum is σ = 66994200. Its totient is φ = 5496768.

The previous prime is 20613239. The next prime is 20613253. The reversal of 20613240 is 4231602.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 28270 + ... + 28989.

Almost surely, 2^20613240 is an apocalyptic number.

20613240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20613240 is an abundant number, since it is smaller than the sum of its proper divisors (46380960).

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

20613240 is a wasteful number, since it uses less digits than its factorization.

20613240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57276 (or 57269 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 18.

The square root of 20613240 is about 4540.1806131475. The cubic root of 20613240 is about 274.1881954292.

Adding to 20613240 its reverse (4231602), we get a palindrome (24844842).

The spelling of 20613240 in words is "twenty million, six hundred thirteen thousand, two hundred forty".