20399136 has 48 divisors (see below), whose sum is σ = 55004544. Its totient is φ = 6614784.

The previous prime is 20399129. The next prime is 20399177. The reversal of 20399136 is 63199302.

It is a tau number, because it is divible by the number of its divisors (48).

It is a super-2 number, since 2×20399136² = 832249499092992, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20399097 and 20399106.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 681 + ... + 6423.

It is an arithmetic number, because the mean of its divisors is an integer number (1145928).

Almost surely, 2^20399136 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20399136, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27502272).

20399136 is an abundant number, since it is smaller than the sum of its proper divisors (34605408).

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

20399136 is a wasteful number, since it uses less digits than its factorization.

20399136 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5793 (or 5785 counting only the distinct ones).

The product of its (nonzero) digits is 8748, while the sum is 33.

The square root of 20399136 is about 4516.5402688341. The cubic root of 20399136 is about 273.2355840570.

It can be divided in two parts, 2039 and 9136, that added together give a triangular number (11175 = T₁₄₉).

The spelling of 20399136 in words is "twenty million, three hundred ninety-nine thousand, one hundred thirty-six".