20706881 has 8 divisors (see below), whose sum is σ = 22530984. Its totient is φ = 18915840.

The previous prime is 20706871. The next prime is 20706929. The reversal of 20706881 is 18860702.

It can be written as a sum of positive squares in 4 ways, for example, as 600625 + 20106256 = 775^2 + 4484^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 20706881 - 2¹⁴ = 20690497 is a prime.

It is a super-2 number, since 2×20706881² = 857549841496322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20706821) 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, 6950 + ... + 9471.

It is an arithmetic number, because the mean of its divisors is an integer number (2816373).

Almost surely, 2^20706881 is an apocalyptic number.

It is an amenable number.

20706881 is a deficient number, since it is larger than the sum of its proper divisors (1824103).

20706881 is a wasteful number, since it uses less digits than its factorization.

20706881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16531.

The product of its (nonzero) digits is 5376, while the sum is 32.

The square root of 20706881 is about 4550.4814031045. The cubic root of 20706881 is about 274.6027586871.

The spelling of 20706881 in words is "twenty million, seven hundred six thousand, eight hundred eighty-one".