20457993 has 8 divisors (see below), whose sum is σ = 27365728. Its totient is φ = 13594464.

The previous prime is 20457977. The next prime is 20458007. The reversal of 20457993 is 39975402.

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

It is not a de Polignac number, because 20457993 - 2⁴ = 20457977 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20457193) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9955 + ... + 11832.

It is an arithmetic number, because the mean of its divisors is an integer number (3420716).

Almost surely, 2^20457993 is an apocalyptic number.

It is an amenable number.

20457993 is a deficient number, since it is larger than the sum of its proper divisors (6907735).

20457993 is a wasteful number, since it uses less digits than its factorization.

20457993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22103.

The product of its (nonzero) digits is 68040, while the sum is 39.

The square root of 20457993 is about 4523.0512930985. The cubic root of 20457993 is about 273.4981178021.

The spelling of 20457993 in words is "twenty million, four hundred fifty-seven thousand, nine hundred ninety-three".