21511439331 has 4 divisors (see below), whose sum is σ = 28681919112. Its totient is φ = 14340959552.

The previous prime is 21511439329. The next prime is 21511439351. The reversal of 21511439331 is 13393411512.

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 21511439331 - 2¹ = 21511439329 is a prime.

It is a super-2 number, since 2×21511439331² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21511439292 and 21511439301.

It is not an unprimeable number, because it can be changed into a prime (21511439351) 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, 3585239886 + ... + 3585239891.

It is an arithmetic number, because the mean of its divisors is an integer number (7170479778).

Almost surely, 2^21511439331 is an apocalyptic number.

21511439331 is a deficient number, since it is larger than the sum of its proper divisors (7170479781).

21511439331 is an equidigital number, since it uses as much as digits as its factorization.

21511439331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7170479780.

The product of its digits is 9720, while the sum is 33.

The spelling of 21511439331 in words is "twenty-one billion, five hundred eleven million, four hundred thirty-nine thousand, three hundred thirty-one".