20917404 has 72 divisors (see below), whose sum is σ = 56805840. Its totient is φ = 6469632.

The previous prime is 20917367. The next prime is 20917409. The reversal of 20917404 is 40471902.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20917409) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 35964 + ... + 36540.

It is an arithmetic number, because the mean of its divisors is an integer number (788970).

Almost surely, 2^20917404 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20917404, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28402920).

20917404 is an abundant number, since it is smaller than the sum of its proper divisors (35888436).

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

20917404 is a wasteful number, since it uses less digits than its factorization.

20917404 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 659 (or 654 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 27.

The square root of 20917404 is about 4573.5548537216. The cubic root of 20917404 is about 275.5302342854.

It can be divided in two parts, 20917 and 404, that added together give a triangular number (21321 = T₂₀₆).

The spelling of 20917404 in words is "twenty million, nine hundred seventeen thousand, four hundred four".