21278247001 has 12 divisors (see below), whose sum is σ = 23422425712. Its totient is φ = 19315791000.

The previous prime is 21278246989. The next prime is 21278247037. The reversal of 21278247001 is 10074287212.

It is a happy number.

It is not a de Polignac number, because 21278247001 - 2²⁵ = 21244692569 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21278247901) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 43635 + ... + 210856.

Almost surely, 2^21278247001 is an apocalyptic number.

It is an amenable number.

21278247001 is a deficient number, since it is larger than the sum of its proper divisors (2144178711).

21278247001 is a wasteful number, since it uses less digits than its factorization.

21278247001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 255204 (or 255193 counting only the distinct ones).

The product of its (nonzero) digits is 12544, while the sum is 34.

The spelling of 21278247001 in words is "twenty-one billion, two hundred seventy-eight million, two hundred forty-seven thousand, one".