20717890 has 32 divisors (see below), whose sum is σ = 38880000. Its totient is φ = 7939008.

The previous prime is 20717869. The next prime is 20717897. The reversal of 20717890 is 9871702.

It is not an unprimeable number, because it can be changed into a prime (20717897) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 57531 + ... + 57889.

It is an arithmetic number, because the mean of its divisors is an integer number (1215000).

Almost surely, 2^20717890 is an apocalyptic number.

20717890 is a deficient number, since it is larger than the sum of its proper divisors (18162110).

20717890 is a wasteful number, since it uses less digits than its factorization.

20717890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 594.

The product of its (nonzero) digits is 7056, while the sum is 34.

The square root of 20717890 is about 4551.6908946017. The cubic root of 20717890 is about 274.6514150762.

The spelling of 20717890 in words is "twenty million, seven hundred seventeen thousand, eight hundred ninety".