20712861 has 16 divisors (see below), whose sum is σ = 33046720. Its totient is φ = 12746160.

The previous prime is 20712847. The next prime is 20712871. The reversal of 20712861 is 16821702.

20712861 = 274² + 275² + ... + 435².

It is not a de Polignac number, because 20712861 - 2⁵ = 20712829 is a prime.

It is a super-2 number, since 2×20712861² = 858045221610642, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

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 (20712841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 29155 + ... + 29856.

It is an arithmetic number, because the mean of its divisors is an integer number (2065420).

Almost surely, 2^20712861 is an apocalyptic number.

It is an amenable number.

20712861 is a deficient number, since it is larger than the sum of its proper divisors (12333859).

20712861 is a wasteful number, since it uses less digits than its factorization.

20712861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59033 (or 59027 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 27.

The square root of 20712861 is about 4551.1384290087. The cubic root of 20712861 is about 274.6291905842.

The spelling of 20712861 in words is "twenty million, seven hundred twelve thousand, eight hundred sixty-one".