21226781015 has 8 divisors (see below), whose sum is σ = 27787786128. Its totient is φ = 15437658880.

The previous prime is 21226781011. The next prime is 21226781027. The reversal of 21226781015 is 51018762212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21226781015 - 2² = 21226781011 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21226781011) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 192970682 + ... + 192970791.

It is an arithmetic number, because the mean of its divisors is an integer number (3473473266).

Almost surely, 2^21226781015 is an apocalyptic number.

21226781015 is a deficient number, since it is larger than the sum of its proper divisors (6561005113).

21226781015 is a wasteful number, since it uses less digits than its factorization.

21226781015 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 385941489.

The product of its (nonzero) digits is 13440, while the sum is 35.

The spelling of 21226781015 in words is "twenty-one billion, two hundred twenty-six million, seven hundred eighty-one thousand, fifteen".