20842723 has 4 divisors (see below), whose sum is σ = 22737528. Its totient is φ = 18947920.

The previous prime is 20842721. The next prime is 20842733. The reversal of 20842723 is 32724802.

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

It is a cyclic number.

It is not a de Polignac number, because 20842723 - 2¹ = 20842721 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20842691 and 20842700.

It is not an unprimeable number, because it can be changed into a prime (20842721) 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, 947386 + ... + 947407.

It is an arithmetic number, because the mean of its divisors is an integer number (5684382).

Almost surely, 2^20842723 is an apocalyptic number.

20842723 is a deficient number, since it is larger than the sum of its proper divisors (1894805).

20842723 is a wasteful number, since it uses less digits than its factorization.

20842723 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1894804.

The product of its (nonzero) digits is 5376, while the sum is 28.

The square root of 20842723 is about 4565.3831164536. The cubic root of 20842723 is about 275.2019365272.

The spelling of 20842723 in words is "twenty million, eight hundred forty-two thousand, seven hundred twenty-three".