21200421531 has 8 divisors (see below), whose sum is σ = 28489805824. Its totient is φ = 14022325800.

The previous prime is 21200421527. The next prime is 21200421533. The reversal of 21200421531 is 13512400212.

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

It is not a de Polignac number, because 21200421531 - 2² = 21200421527 is a prime.

It is a super-2 number, since 2×21200421531² (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 = 21200421498 and 21200421507.

It is not an unprimeable number, because it can be changed into a prime (21200421533) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27821695 + ... + 27822456.

It is an arithmetic number, because the mean of its divisors is an integer number (3561225728).

Almost surely, 2^21200421531 is an apocalyptic number.

21200421531 is a deficient number, since it is larger than the sum of its proper divisors (7289384293).

21200421531 is a wasteful number, since it uses less digits than its factorization.

21200421531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55644281.

The product of its (nonzero) digits is 480, while the sum is 21.

Adding to 21200421531 its reverse (13512400212), we get a palindrome (34712821743).

The spelling of 21200421531 in words is "twenty-one billion, two hundred million, four hundred twenty-one thousand, five hundred thirty-one".