20726861 has 4 divisors (see below), whose sum is σ = 20771712. Its totient is φ = 20682012.

The previous prime is 20726837. The next prime is 20726897. The reversal of 20726861 is 16862702.

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, and also an emirpimes, since its reverse is a distinct semiprime: 16862702 = 2 ⋅8431351.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20726861 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20726801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21725 + ... + 22658.

It is an arithmetic number, because the mean of its divisors is an integer number (5192928).

Almost surely, 2^20726861 is an apocalyptic number.

It is an amenable number.

20726861 is a deficient number, since it is larger than the sum of its proper divisors (44851).

20726861 is an equidigital number, since it uses as much as digits as its factorization.

20726861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44850.

The product of its (nonzero) digits is 8064, while the sum is 32.

The square root of 20726861 is about 4552.6762459020. The cubic root of 20726861 is about 274.6910513889.

The spelling of 20726861 in words is "twenty million, seven hundred twenty-six thousand, eight hundred sixty-one".