21540239226 has 96 divisors (see below), whose sum is σ = 52836537600. Its totient is φ = 6499785600.

The previous prime is 21540239213. The next prime is 21540239233. The reversal of 21540239226 is 62293204512.

21540239226 is a `hidden beast` number, since 2 + 1 + 540 + 2 + 3 + 92 + 26 = 666.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1567855 + ... + 1581533.

It is an arithmetic number, because the mean of its divisors is an integer number (550380600).

Almost surely, 2^21540239226 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21540239226, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26418268800).

21540239226 is an abundant number, since it is smaller than the sum of its proper divisors (31296298374).

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

21540239226 is a wasteful number, since it uses less digits than its factorization.

21540239226 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13953 (or 13936 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

The spelling of 21540239226 in words is "twenty-one billion, five hundred forty million, two hundred thirty-nine thousand, two hundred twenty-six".