20873731 has 4 divisors (see below), whose sum is σ = 21026232. Its totient is φ = 20721232.

The previous prime is 20873729. The next prime is 20873737. The reversal of 20873731 is 13737802.

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 20873731 - 2¹ = 20873729 is a prime.

It is a super-2 number, since 2×20873731² = 871425291720722, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) 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 a junction number, because it is equal to n+sod(n) for n = 20873693 and 20873702.

It is not an unprimeable number, because it can be changed into a prime (20873737) 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, 76045 + ... + 76318.

It is an arithmetic number, because the mean of its divisors is an integer number (5256558).

Almost surely, 2^20873731 is an apocalyptic number.

20873731 is a deficient number, since it is larger than the sum of its proper divisors (152501).

20873731 is a wasteful number, since it uses less digits than its factorization.

20873731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 152500.

The product of its (nonzero) digits is 7056, while the sum is 31.

The square root of 20873731 is about 4568.7778453324. Note that the first 3 decimals coincide. The cubic root of 20873731 is about 275.3383427822.

The spelling of 20873731 in words is "twenty million, eight hundred seventy-three thousand, seven hundred thirty-one".