20463781 has 4 divisors (see below), whose sum is σ = 22037932. Its totient is φ = 18889632.

The previous prime is 20463761. The next prime is 20463787. The reversal of 20463781 is 18736402.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18736402 = 2 ⋅9368201.

It can be written as a sum of positive squares in 2 ways, for example, as 9180900 + 11282881 = 3030^2 + 3359^2 .

It is a cyclic number.

It is not a de Polignac number, because 20463781 - 2⁹ = 20463269 is a prime.

It is a super-2 number, since 2×20463781² = 837532665631922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20463787) 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, 787056 + ... + 787081.

It is an arithmetic number, because the mean of its divisors is an integer number (5509483).

Almost surely, 2^20463781 is an apocalyptic number.

It is an amenable number.

20463781 is a deficient number, since it is larger than the sum of its proper divisors (1574151).

20463781 is a wasteful number, since it uses less digits than its factorization.

20463781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1574150.

The product of its (nonzero) digits is 8064, while the sum is 31.

The square root of 20463781 is about 4523.6910814069. The cubic root of 20463781 is about 273.5239081756.

The spelling of 20463781 in words is "twenty million, four hundred sixty-three thousand, seven hundred eighty-one".