21420432031 has 4 divisors (see below), whose sum is σ = 21876185952. Its totient is φ = 20964678112.

The previous prime is 21420432029. The next prime is 21420432037. The reversal of 21420432031 is 13023402412.

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 21420432031 - 2¹ = 21420432029 is a prime.

It is a super-2 number, since 2×21420432031² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21420431993 and 21420432011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21420432037) 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, 227876890 + ... + 227876983.

It is an arithmetic number, because the mean of its divisors is an integer number (5469046488).

Almost surely, 2^21420432031 is an apocalyptic number.

21420432031 is a deficient number, since it is larger than the sum of its proper divisors (455753921).

21420432031 is an equidigital number, since it uses as much as digits as its factorization.

21420432031 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 455753920.

The product of its (nonzero) digits is 1152, while the sum is 22.

Adding to 21420432031 its reverse (13023402412), we get a palindrome (34443834443).

The spelling of 21420432031 in words is "twenty-one billion, four hundred twenty million, four hundred thirty-two thousand, thirty-one".