20742736 has 40 divisors (see below), whose sum is σ = 46247040. Its totient is φ = 8828544.

The previous prime is 20742713. The next prime is 20742763. The reversal of 20742736 is 63724702.

It is a happy number.

It is a super-2 number, since 2×20742736² = 860522193531392, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20742698 and 20742707.

It is a congruent number.

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, 18150 + ... + 19258.

It is an arithmetic number, because the mean of its divisors is an integer number (1156176).

Almost surely, 2^20742736 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 20742736, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23123520).

20742736 is an abundant number, since it is smaller than the sum of its proper divisors (25504304).

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

20742736 is a wasteful number, since it uses less digits than its factorization.

20742736 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1291 (or 1285 counting only the distinct ones).

The product of its (nonzero) digits is 14112, while the sum is 31.

The square root of 20742736 is about 4554.4193921948. The cubic root of 20742736 is about 274.7611634302.

The spelling of 20742736 in words is "twenty million, seven hundred forty-two thousand, seven hundred thirty-six".