20745999 has 6 divisors (see below), whose sum is σ = 29966456. Its totient is φ = 13830660.

The previous prime is 20745983. The next prime is 20746007. The reversal of 20745999 is 99954702.

It is not a de Polignac number, because 20745999 - 2⁴ = 20745983 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20745799) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1152547 + ... + 1152564.

Almost surely, 2^20745999 is an apocalyptic number.

20745999 is a deficient number, since it is larger than the sum of its proper divisors (9220457).

20745999 is a wasteful number, since it uses less digits than its factorization.

20745999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2305117 (or 2305114 counting only the distinct ones).

The product of its (nonzero) digits is 204120, while the sum is 45.

The square root of 20745999 is about 4554.7776015959. Note that the first 3 decimals coincide. The cubic root of 20745999 is about 274.7755700586.

The spelling of 20745999 in words is "twenty million, seven hundred forty-five thousand, nine hundred ninety-nine".