20399340 has 48 divisors (see below), whose sum is σ = 61514208. Its totient is φ = 5021184.

The previous prime is 20399299. The next prime is 20399341. The reversal of 20399340 is 4399302.

It is a super-2 number, since 2×20399340² = 832266144871200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 20399298 and 20399307.

It is not an unprimeable number, because it can be changed into a prime (20399341) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 12297 + ... + 13856.

It is an arithmetic number, because the mean of its divisors is an integer number (1281546).

Almost surely, 2^20399340 is an apocalyptic number.

20399340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20399340 is an abundant number, since it is smaller than the sum of its proper divisors (41114868).

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

20399340 is a wasteful number, since it uses less digits than its factorization.

20399340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26178 (or 26176 counting only the distinct ones).

The product of its (nonzero) digits is 5832, while the sum is 30.

The square root of 20399340 is about 4516.5628524355. The cubic root of 20399340 is about 273.2364948778.

The spelling of 20399340 in words is "twenty million, three hundred ninety-nine thousand, three hundred forty".