20870817 has 16 divisors (see below), whose sum is σ = 30932928. Its totient is φ = 12409280.

The previous prime is 20870813. The next prime is 20870869. The reversal of 20870817 is 71807802.

It is a cyclic number.

It is not a de Polignac number, because 20870817 - 2² = 20870813 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is not an unprimeable number, because it can be changed into a prime (20870813) 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, 4218 + ... + 7715.

It is an arithmetic number, because the mean of its divisors is an integer number (1933308).

Almost surely, 2^20870817 is an apocalyptic number.

It is an amenable number.

20870817 is a deficient number, since it is larger than the sum of its proper divisors (10062111).

20870817 is a wasteful number, since it uses less digits than its factorization.

20870817 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12000.

The product of its (nonzero) digits is 6272, while the sum is 33.

The square root of 20870817 is about 4568.4589305366. The cubic root of 20870817 is about 275.3255296556.

The spelling of 20870817 in words is "twenty million, eight hundred seventy thousand, eight hundred seventeen".