20726640 has 120 divisors (see below), whose sum is σ = 75963888. Its totient is φ = 5022720.

The previous prime is 20726627. The next prime is 20726647. The reversal of 20726640 is 4662702.

20726640 = T₂₄₉ + T₂₅₀ + ... + T₅₁₈.

It is a tau number, because it is divible by the number of its divisors (120).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20726647) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6612 + ... + 9228.

Almost surely, 2^20726640 is an apocalyptic number.

20726640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20726640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37981944).

20726640 is an abundant number, since it is smaller than the sum of its proper divisors (55237248).

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

20726640 is a wasteful number, since it uses less digits than its factorization.

20726640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2647 (or 2638 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 27.

The square root of 20726640 is about 4552.6519743991. The cubic root of 20726640 is about 274.6900750884.

The spelling of 20726640 in words is "twenty million, seven hundred twenty-six thousand, six hundred forty".