20620681 has 9 divisors (see below), whose sum is σ = 21854541. Its totient is φ = 19453644.

The previous prime is 20620679. The next prime is 20620687. The reversal of 20620681 is 18602602.

The square root of 20620681 is 4541.

It is a perfect power (a square), and thus also a powerful number.

It is not a de Polignac number, because 20620681 - 2¹ = 20620679 is a prime.

It is a super-2 number, since 2×20620681² = 850424969807522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20620687) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 86160 + ... + 86398.

Almost surely, 2^20620681 is an apocalyptic number.

20620681 is the 4541-st square number.

20620681 is the 2271-st centered octagonal number.

It is an amenable number.

20620681 is a deficient number, since it is larger than the sum of its proper divisors (1233860).

20620681 is an frugal number, since it uses more digits than its factorization.

20620681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 516 (or 258 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 25.

The cubic root of 20620681 is about 274.2211837564.

Multiplying 20620681 by its sum of digits (25), we get a square (515517025 = 22705²).

The spelling of 20620681 in words is "twenty million, six hundred twenty thousand, six hundred eighty-one".