21505434274 has 24 divisors (see below), whose sum is σ = 32993073360. Its totient is φ = 10510177680.

The previous prime is 21505434241. The next prime is 21505434281. The reversal of 21505434274 is 47243450512.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3863017 + ... + 3868579.

It is an arithmetic number, because the mean of its divisors is an integer number (1374711390).

Almost surely, 2^21505434274 is an apocalyptic number.

21505434274 is a deficient number, since it is larger than the sum of its proper divisors (11487639086).

21505434274 is an equidigital number, since it uses as much as digits as its factorization.

21505434274 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5986 (or 5805 counting only the distinct ones).

The product of its (nonzero) digits is 134400, while the sum is 37.

Adding to 21505434274 its reverse (47243450512), we get a palindrome (68748884786).

The spelling of 21505434274 in words is "twenty-one billion, five hundred five million, four hundred thirty-four thousand, two hundred seventy-four".