20601643 has 4 divisors (see below), whose sum is σ = 21685960. Its totient is φ = 19517328.

The previous prime is 20601617. The next prime is 20601667. The reversal of 20601643 is 34610602.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20601643 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20601613) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 542130 + ... + 542167.

It is an arithmetic number, because the mean of its divisors is an integer number (5421490).

Almost surely, 2^20601643 is an apocalyptic number.

20601643 is a deficient number, since it is larger than the sum of its proper divisors (1084317).

20601643 is a wasteful number, since it uses less digits than its factorization.

20601643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1084316.

The product of its (nonzero) digits is 864, while the sum is 22.

The square root of 20601643 is about 4538.9032816309. The cubic root of 20601643 is about 274.1367663962.

The spelling of 20601643 in words is "twenty million, six hundred one thousand, six hundred forty-three".