21507532320371 has 4 divisors (see below), whose sum is σ = 21507542627832. Its totient is φ = 21507522012912.

The previous prime is 21507532320361. The next prime is 21507532320389. The reversal of 21507532320371 is 17302323570512.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21507532320371 is a prime.

It is a super-4 number, since 4×21507532320371⁴ (a number of 54 digits) contains 4444 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21507532320361) 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, 795101 + ... + 6606606.

It is an arithmetic number, because the mean of its divisors is an integer number (5376885656958).

Almost surely, 2^{21507532320371} is an apocalyptic number.

21507532320371 is a deficient number, since it is larger than the sum of its proper divisors (10307461).

21507532320371 is an equidigital number, since it uses as much as digits as its factorization.

21507532320371 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10307460.

The product of its (nonzero) digits is 264600, while the sum is 41.

Adding to 21507532320371 its reverse (17302323570512), we get a palindrome (38809855890883).

The spelling of 21507532320371 in words is "twenty-one trillion, five hundred seven billion, five hundred thirty-two million, three hundred twenty thousand, three hundred seventy-one".