21438707615 has 8 divisors (see below), whose sum is σ = 27705406848. Its totient is φ = 15831660960.

The previous prime is 21438707581. The next prime is 21438707617. The reversal of 21438707615 is 51670783412.

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

It is not a de Polignac number, because 21438707615 - 2³² = 17143740319 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 (21438707617) 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, 164913071 + ... + 164913200.

It is an arithmetic number, because the mean of its divisors is an integer number (3463175856).

Almost surely, 2^21438707615 is an apocalyptic number.

21438707615 is a deficient number, since it is larger than the sum of its proper divisors (6266699233).

21438707615 is a wasteful number, since it uses less digits than its factorization.

21438707615 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 329826289.

The product of its (nonzero) digits is 282240, while the sum is 44.

The spelling of 21438707615 in words is "twenty-one billion, four hundred thirty-eight million, seven hundred seven thousand, six hundred fifteen".