20239999 has 16 divisors (see below), whose sum is σ = 23173920. Its totient is φ = 17539200.

The previous prime is 20239991. The next prime is 20240021. The reversal of 20239999 is 99993202.

It is not a de Polignac number, because 20239999 - 2³ = 20239991 is a prime.

It is a Duffinian number.

20239999 is a modest number, since divided by 9999 gives 2023 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20239991) 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, 13224 + ... + 14674.

It is an arithmetic number, because the mean of its divisors is an integer number (1448370).

Almost surely, 2^20239999 is an apocalyptic number.

20239999 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

20239999 is a deficient number, since it is larger than the sum of its proper divisors (2933921).

20239999 is a wasteful number, since it uses less digits than its factorization.

20239999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1530.

The product of its (nonzero) digits is 78732, while the sum is 43.

The square root of 20239999 is about 4498.8886405422. Note that the first 3 decimals coincide. The cubic root of 20239999 is about 272.5232098739.

The spelling of 20239999 in words is "twenty million, two hundred thirty-nine thousand, nine hundred ninety-nine".