20121431 has 4 divisors (see below), whose sum is σ = 21950664. Its totient is φ = 18292200.

The previous prime is 20121427. The next prime is 20121433. The reversal of 20121431 is 13412102.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20121431 - 2² = 20121427 is a prime.

It is a super-2 number, since 2×20121431² = 809743970975522, 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 (20121433) 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 3 ways as a sum of consecutive naturals, for example, 914600 + ... + 914621.

It is an arithmetic number, because the mean of its divisors is an integer number (5487666).

Almost surely, 2^20121431 is an apocalyptic number.

20121431 is a deficient number, since it is larger than the sum of its proper divisors (1829233).

20121431 is a wasteful number, since it uses less digits than its factorization.

20121431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1829232.

The product of its (nonzero) digits is 48, while the sum is 14.

The square root of 20121431 is about 4485.6918084059. The cubic root of 20121431 is about 271.9900109870.

Adding to 20121431 its reverse (13412102), we get a palindrome (33533533).

It can be divided in two parts, 2012 and 1431, that added together give a palindrome (3443).

The spelling of 20121431 in words is "twenty million, one hundred twenty-one thousand, four hundred thirty-one".