21266332506 has 24 divisors (see below), whose sum is σ = 47563411584. Its totient is φ = 6860107080.

The previous prime is 21266332471. The next prime is 21266332511. The reversal of 21266332506 is 60523366212.

21266332506 is a `hidden beast` number, since 2 + 12 + 6 + 633 + 2 + 5 + 0 + 6 = 666.

It is a Curzon number.

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, 19055296 + ... + 19056411.

It is an arithmetic number, because the mean of its divisors is an integer number (1981808816).

Almost surely, 2^21266332506 is an apocalyptic number.

21266332506 is an abundant number, since it is smaller than the sum of its proper divisors (26297079078).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21266332506 is a wasteful number, since it uses less digits than its factorization.

21266332506 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38111746 (or 38111743 counting only the distinct ones).

The product of its (nonzero) digits is 77760, while the sum is 36.

Adding to 21266332506 its reverse (60523366212), we get a palindrome (81789698718).

The spelling of 21266332506 in words is "twenty-one billion, two hundred sixty-six million, three hundred thirty-two thousand, five hundred six".