20840693 has 4 divisors (see below), whose sum is σ = 21284160. Its totient is φ = 20397228.

The previous prime is 20840683. The next prime is 20840707. The reversal of 20840693 is 39604802.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20840693 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20840653) 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, 221663 + ... + 221756.

It is an arithmetic number, because the mean of its divisors is an integer number (5321040).

Almost surely, 2^20840693 is an apocalyptic number.

It is an amenable number.

20840693 is a deficient number, since it is larger than the sum of its proper divisors (443467).

20840693 is an equidigital number, since it uses as much as digits as its factorization.

20840693 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 443466.

The product of its (nonzero) digits is 10368, while the sum is 32.

The square root of 20840693 is about 4565.1607857774. The cubic root of 20840693 is about 275.1930017051.

The spelling of 20840693 in words is "twenty million, eight hundred forty thousand, six hundred ninety-three".