20472781 has 8 divisors (see below), whose sum is σ = 23582720. Its totient is φ = 17409168.

The previous prime is 20472769. The next prime is 20472797. The reversal of 20472781 is 18727402.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20472781 - 2⁹ = 20472269 is a prime.

It is a super-4 number, since 4×20472781⁴ (a number of 30 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20472181) 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 7 ways as a sum of consecutive naturals, for example, 10626 + ... + 12403.

It is an arithmetic number, because the mean of its divisors is an integer number (2947840).

Almost surely, 2^20472781 is an apocalyptic number.

It is an amenable number.

20472781 is a deficient number, since it is larger than the sum of its proper divisors (3109939).

20472781 is a wasteful number, since it uses less digits than its factorization.

20472781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23163.

The product of its (nonzero) digits is 6272, while the sum is 31.

The square root of 20472781 is about 4524.6857349434. The cubic root of 20472781 is about 273.5640010332.

The spelling of 20472781 in words is "twenty million, four hundred seventy-two thousand, seven hundred eighty-one".