20656240 has 40 divisors (see below), whose sum is σ = 52393968. Its totient is φ = 7511040.

The previous prime is 20656219. The next prime is 20656253. The reversal of 20656240 is 4265602.

It is a tau number, because it is divible by the number of its divisors (40).

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 7 ways as a sum of consecutive naturals, for example, 10857 + ... + 12616.

Almost surely, 2^20656240 is an apocalyptic number.

20656240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20656240 is an abundant number, since it is smaller than the sum of its proper divisors (31737728).

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

20656240 is a wasteful number, since it uses less digits than its factorization.

20656240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23497 (or 23491 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 25.

The square root of 20656240 is about 4544.9136405437. The cubic root of 20656240 is about 274.3787186673.

It can be divided in two parts, 206562 and 40, that added together give a palindrome (206602).

The spelling of 20656240 in words is "twenty million, six hundred fifty-six thousand, two hundred forty".