20645642 has 8 divisors (see below), whose sum is σ = 31027332. Its totient is φ = 10303200.

The previous prime is 20645579. The next prime is 20645671. The reversal of 20645642 is 24654602.

It can be written as a sum of positive squares in 2 ways, for example, as 19545241 + 1100401 = 4421^2 + 1049^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

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, 8459 + ... + 10622.

Almost surely, 2^20645642 is an apocalyptic number.

20645642 is a deficient number, since it is larger than the sum of its proper divisors (10381690).

20645642 is a wasteful number, since it uses less digits than its factorization.

20645642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19624.

The product of its (nonzero) digits is 11520, while the sum is 29.

The square root of 20645642 is about 4543.7475722139. The cubic root of 20645642 is about 274.3317859066.

The spelling of 20645642 in words is "twenty million, six hundred forty-five thousand, six hundred forty-two".