20399900 has 18 divisors (see below), whose sum is σ = 44268000. Its totient is φ = 8159920.

The previous prime is 20399887. The next prime is 20399909. The reversal of 20399900 is 999302.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20399909) 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 5 ways as a sum of consecutive naturals, for example, 101900 + ... + 102099.

Almost surely, 2^20399900 is an apocalyptic number.

20399900 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20399900 is an abundant number, since it is smaller than the sum of its proper divisors (23868100).

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

20399900 is a wasteful number, since it uses less digits than its factorization.

20399900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 204013 (or 204006 counting only the distinct ones).

The product of its (nonzero) digits is 4374, while the sum is 32.

The square root of 20399900 is about 4516.6248460549. The cubic root of 20399900 is about 273.2389951390.

It can be divided in two parts, 20 and 399900, that multiplied together give a triangular number (7998000 = T₃₉₉₉).

The spelling of 20399900 in words is "twenty million, three hundred ninety-nine thousand, nine hundred".