20439940 has 24 divisors (see below), whose sum is σ = 43088472. Its totient is φ = 8144640.

The previous prime is 20439931. The next prime is 20439959. The reversal of 20439940 is 4993402.

It can be written as a sum of positive squares in 4 ways, for example, as 207936 + 20232004 = 456^2 + 4498^2 .

It is a super-2 number, since 2×20439940² = 835582294407200, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3802 + ... + 7438.

It is an arithmetic number, because the mean of its divisors is an integer number (1795353).

Almost surely, 2^20439940 is an apocalyptic number.

20439940 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20439940 is an abundant number, since it is smaller than the sum of its proper divisors (22648532).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20439940 is a wasteful number, since it uses less digits than its factorization.

20439940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3927 (or 3925 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 31.

The square root of 20439940 is about 4521.0551865687. The cubic root of 20439940 is about 273.4176453502.

The spelling of 20439940 in words is "twenty million, four hundred thirty-nine thousand, nine hundred forty".