20281239 has 32 divisors (see below), whose sum is σ = 34214400. Its totient is φ = 11753280.

The previous prime is 20281229. The next prime is 20281241. The reversal of 20281239 is 93218202.

It is a happy number.

It is not a de Polignac number, because 20281239 - 2¹² = 20277143 is a prime.

It is a super-2 number, since 2×20281239² = 822657310750242, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20281229) 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, 5347 + ... + 8315.

It is an arithmetic number, because the mean of its divisors is an integer number (1069200).

Almost surely, 2^20281239 is an apocalyptic number.

20281239 is a deficient number, since it is larger than the sum of its proper divisors (13933161).

20281239 is a wasteful number, since it uses less digits than its factorization.

20281239 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3012 (or 3006 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 20281239 is about 4503.4696623826. The cubic root of 20281239 is about 272.7081774812.

20281239 divided by its sum of digits (27) gives a palindrome (751157).

The spelling of 20281239 in words is "twenty million, two hundred eighty-one thousand, two hundred thirty-nine".