20720187 has 6 divisors (see below), whose sum is σ = 29929172. Its totient is φ = 13813452.

The previous prime is 20720153. The next prime is 20720209. The reversal of 20720187 is 78102702.

It is not a de Polignac number, because 20720187 - 2¹⁸ = 20458043 is a prime.

It is a super-2 number, since 2×20720187² = 858652298629938, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20720187.

It is not an unprimeable number, because it can be changed into a prime (20720107) 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, 1151113 + ... + 1151130.

Almost surely, 2^20720187 is an apocalyptic number.

20720187 is a deficient number, since it is larger than the sum of its proper divisors (9208985).

20720187 is a wasteful number, since it uses less digits than its factorization.

20720187 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2302249 (or 2302246 counting only the distinct ones).

The product of its (nonzero) digits is 1568, while the sum is 27.

The square root of 20720187 is about 4551.9432114208. The cubic root of 20720187 is about 274.6615649352.

Adding to 20720187 its reverse (78102702), we get a palindrome (98822889).

The spelling of 20720187 in words is "twenty million, seven hundred twenty thousand, one hundred eighty-seven".