21278426915 has 8 divisors (see below), whose sum is σ = 25538986368. Its totient is φ = 17019492160.

The previous prime is 21278426899. The next prime is 21278426927. The reversal of 21278426915 is 51962487212.

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

It is not a de Polignac number, because 21278426915 - 2⁴ = 21278426899 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21278426915.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 377171 + ... + 429900.

It is an arithmetic number, because the mean of its divisors is an integer number (3192373296).

Almost surely, 2^21278426915 is an apocalyptic number.

21278426915 is a deficient number, since it is larger than the sum of its proper divisors (4260559453).

21278426915 is an equidigital number, since it uses as much as digits as its factorization.

21278426915 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 812349.

The product of its digits is 483840, while the sum is 47.

The spelling of 21278426915 in words is "twenty-one billion, two hundred seventy-eight million, four hundred twenty-six thousand, nine hundred fifteen".