20280861 has 20 divisors (see below), whose sum is σ = 30457152. Its totient is φ = 13448808.

The previous prime is 20280859. The next prime is 20280877. The reversal of 20280861 is 16808202.

It is not a de Polignac number, because 20280861 - 2¹ = 20280859 is a prime.

It is a super-2 number, since 2×20280861² = 822626645802642, which contains 22 as substring.

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

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20280811) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 17836 + ... + 18938.

Almost surely, 2^20280861 is an apocalyptic number.

It is an amenable number.

20280861 is a deficient number, since it is larger than the sum of its proper divisors (10176291).

20280861 is a wasteful number, since it uses less digits than its factorization.

20280861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1342 (or 1333 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 27.

The square root of 20280861 is about 4503.4276945456. The cubic root of 20280861 is about 272.7064832335.

The spelling of 20280861 in words is "twenty million, two hundred eighty thousand, eight hundred sixty-one".