20015720 has 16 divisors (see below), whose sum is σ = 45035460. Its totient is φ = 8006272.

The previous prime is 20015711. The next prime is 20015729. The reversal of 20015720 is 2751002.

It is an interprime number because it is at equal distance from previous prime (20015711) and next prime (20015729).

It can be written as a sum of positive squares in 2 ways, for example, as 19909444 + 106276 = 4462^2 + 326^2 .

It is not an unprimeable number, because it can be changed into a prime (20015729) 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 3 ways as a sum of consecutive naturals, for example, 250157 + ... + 250236.

Almost surely, 2^20015720 is an apocalyptic number.

20015720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20015720 is an abundant number, since it is smaller than the sum of its proper divisors (25019740).

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

20015720 is a wasteful number, since it uses less digits than its factorization.

20015720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 500404 (or 500400 counting only the distinct ones).

The product of its (nonzero) digits is 140, while the sum is 17.

The square root of 20015720 is about 4473.8931592071. The cubic root of 20015720 is about 271.5128607763.

Adding to 20015720 its reverse (2751002), we get a palindrome (22766722).

It can be divided in two parts, 2001 and 5720, that multiplied together give a triangular number (11445720 = T₄₇₈₄).

The spelling of 20015720 in words is "twenty million, fifteen thousand, seven hundred twenty".