20666451 has 16 divisors (see below), whose sum is σ = 29787296. Its totient is φ = 12669696.

The previous prime is 20666447. The next prime is 20666453. The reversal of 20666451 is 15466602.

It is not a de Polignac number, because 20666451 - 2² = 20666447 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20666453) 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 15 ways as a sum of consecutive naturals, for example, 11361 + ... + 13053.

It is an arithmetic number, because the mean of its divisors is an integer number (1861706).

Almost surely, 2^20666451 is an apocalyptic number.

20666451 is a deficient number, since it is larger than the sum of its proper divisors (9120845).

20666451 is a wasteful number, since it uses less digits than its factorization.

20666451 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2022.

The product of its (nonzero) digits is 8640, while the sum is 30.

The square root of 20666451 is about 4546.0368454292. The cubic root of 20666451 is about 274.4239224342.

The spelling of 20666451 in words is "twenty million, six hundred sixty-six thousand, four hundred fifty-one".