20985867 has 36 divisors (see below), whose sum is σ = 36812880. Its totient is φ = 11464992.

The previous prime is 20985857. The next prime is 20985869. The reversal of 20985867 is 76858902.

It is not a de Polignac number, because 20985867 - 2⁷ = 20985739 is a prime.

It is a super-2 number, since 2×20985867² = 880813227483378, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20985869) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 9109 + ... + 11177.

It is an arithmetic number, because the mean of its divisors is an integer number (1022580).

Almost surely, 2^20985867 is an apocalyptic number.

20985867 is a deficient number, since it is larger than the sum of its proper divisors (15827013).

20985867 is a wasteful number, since it uses less digits than its factorization.

20985867 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2112 (or 2102 counting only the distinct ones).

The product of its (nonzero) digits is 241920, while the sum is 45.

The square root of 20985867 is about 4581.0333986995. The cubic root of 20985867 is about 275.8305118828.

The spelling of 20985867 in words is "twenty million, nine hundred eighty-five thousand, eight hundred sixty-seven".