21531322345 has 32 divisors (see below), whose sum is σ = 28478241792. Its totient is φ = 15529542912.

The previous prime is 21531322301. The next prime is 21531322349. The reversal of 21531322345 is 54322313512.

It is not a de Polignac number, because 21531322345 - 2²³ = 21522933737 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21531322349) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 754222 + ... + 782248.

It is an arithmetic number, because the mean of its divisors is an integer number (889945056).

Almost surely, 2^21531322345 is an apocalyptic number.

It is an amenable number.

21531322345 is a deficient number, since it is larger than the sum of its proper divisors (6946919447).

21531322345 is a wasteful number, since it uses less digits than its factorization.

21531322345 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28321.

The product of its digits is 21600, while the sum is 31.

Adding to 21531322345 its reverse (54322313512), we get a palindrome (75853635857).

The spelling of 21531322345 in words is "twenty-one billion, five hundred thirty-one million, three hundred twenty-two thousand, three hundred forty-five".