20737993 has 4 divisors (see below), whose sum is σ = 20843460. Its totient is φ = 20632528.

The previous prime is 20737967. The next prime is 20738021. The reversal of 20737993 is 39973702.

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

It can be written as a sum of positive squares in 2 ways, for example, as 12194064 + 8543929 = 3492^2 + 2923^2 .

It is a cyclic number.

It is not a de Polignac number, because 20737993 - 2⁵ = 20737961 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20737903) 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, 52438 + ... + 52831.

It is an arithmetic number, because the mean of its divisors is an integer number (5210865).

Almost surely, 2^20737993 is an apocalyptic number.

It is an amenable number.

20737993 is a deficient number, since it is larger than the sum of its proper divisors (105467).

20737993 is a wasteful number, since it uses less digits than its factorization.

20737993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 105466.

The product of its (nonzero) digits is 71442, while the sum is 40.

The square root of 20737993 is about 4553.8986593907. The cubic root of 20737993 is about 274.7402196881.

The spelling of 20737993 in words is "twenty million, seven hundred thirty-seven thousand, nine hundred ninety-three".