20787975 has 96 divisors (see below), whose sum is σ = 43330560. Its totient is φ = 9694080.

The previous prime is 20787971. The next prime is 20788003. The reversal of 20787975 is 57978702.

It is not a de Polignac number, because 20787975 - 2² = 20787971 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 20787975.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20787971) 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 95 ways as a sum of consecutive naturals, for example, 201774 + ... + 201876.

It is an arithmetic number, because the mean of its divisors is an integer number (451360).

Almost surely, 2^20787975 is an apocalyptic number.

20787975 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

20787975 is an abundant number, since it is smaller than the sum of its proper divisors (22542585).

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

20787975 is a wasteful number, since it uses less digits than its factorization.

20787975 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 158 (or 147 counting only the distinct ones).

The product of its (nonzero) digits is 246960, while the sum is 45.

The square root of 20787975 is about 4559.3831819666. The cubic root of 20787975 is about 274.9607657526.

The spelling of 20787975 in words is "twenty million, seven hundred eighty-seven thousand, nine hundred seventy-five".