20612281 has 4 divisors (see below), whose sum is σ = 20703312. Its totient is φ = 20521252.

The previous prime is 20612269. The next prime is 20612341. The reversal of 20612281 is 18221602.

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.

It is a cyclic number.

It is not a de Polignac number, because 20612281 - 2¹⁵ = 20579513 is a prime.

It is a super-2 number, since 2×20612281² = 849732256045922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20612201) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 45175 + ... + 45628.

It is an arithmetic number, because the mean of its divisors is an integer number (5175828).

Almost surely, 2^20612281 is an apocalyptic number.

It is an amenable number.

20612281 is a deficient number, since it is larger than the sum of its proper divisors (91031).

20612281 is an equidigital number, since it uses as much as digits as its factorization.

20612281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91030.

The product of its (nonzero) digits is 384, while the sum is 22.

The square root of 20612281 is about 4540.0749993805. The cubic root of 20612281 is about 274.1839432988.

Adding to 20612281 its reverse (18221602), we get a palindrome (38833883).

The spelling of 20612281 in words is "twenty million, six hundred twelve thousand, two hundred eighty-one".