20431047 has 32 divisors (see below), whose sum is σ = 34058752. Its totient is φ = 10606464.

The previous prime is 20431043. The next prime is 20431057. The reversal of 20431047 is 74013402.

It is not a de Polignac number, because 20431047 - 2² = 20431043 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20431043) 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 31 ways as a sum of consecutive naturals, for example, 17733 + ... + 18849.

It is an arithmetic number, because the mean of its divisors is an integer number (1064336).

Almost surely, 2^20431047 is an apocalyptic number.

20431047 is a deficient number, since it is larger than the sum of its proper divisors (13627705).

20431047 is a wasteful number, since it uses less digits than its factorization.

20431047 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1207.

The product of its (nonzero) digits is 672, while the sum is 21.

The square root of 20431047 is about 4520.0715702298. The cubic root of 20431047 is about 273.3779867889.

Adding to 20431047 its reverse (74013402), we get a palindrome (94444449).

The spelling of 20431047 in words is "twenty million, four hundred thirty-one thousand, forty-seven".