20840139 has 32 divisors (see below), whose sum is σ = 33123840. Its totient is φ = 12915936.

The previous prime is 20840123. The next prime is 20840167. The reversal of 20840139 is 93104802.

It is not a de Polignac number, because 20840139 - 2⁴ = 20840123 is a prime.

It is a super-2 number, since 2×20840139² = 868622787078642, 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 (20840639) 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, 22524 + ... + 23430.

It is an arithmetic number, because the mean of its divisors is an integer number (1035120).

Almost surely, 2^20840139 is an apocalyptic number.

20840139 is a deficient number, since it is larger than the sum of its proper divisors (12283701).

20840139 is a wasteful number, since it uses less digits than its factorization.

20840139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 976 (or 970 counting only the distinct ones).

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

The square root of 20840139 is about 4565.1001084314. The cubic root of 20840139 is about 275.1905632341.

The spelling of 20840139 in words is "twenty million, eight hundred forty thousand, one hundred thirty-nine".