20535999 has 32 divisors (see below), whose sum is σ = 31153920. Its totient is φ = 12022560.

The previous prime is 20535947. The next prime is 20536013. The reversal of 20535999 is 99953502.

It is not a de Polignac number, because 20535999 - 2²³ = 12147391 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20535999.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20535929) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 147672 + ... + 147810.

It is an arithmetic number, because the mean of its divisors is an integer number (973560).

Almost surely, 2^20535999 is an apocalyptic number.

20535999 is a deficient number, since it is larger than the sum of its proper divisors (10617921).

20535999 is a wasteful number, since it uses less digits than its factorization.

20535999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 212 (or 190 counting only the distinct ones).

The product of its (nonzero) digits is 109350, while the sum is 42.

The square root of 20535999 is about 4531.6662498467. Note that the first 3 decimals coincide. The cubic root of 20535999 is about 273.8452915685.

The spelling of 20535999 in words is "twenty million, five hundred thirty-five thousand, nine hundred ninety-nine".