21681670001 has 16 divisors (see below), whose sum is σ = 23261644800. Its totient is φ = 20135851008.

The previous prime is 21681669991. The next prime is 21681670033. The reversal of 21681670001 is 10007618612.

It is a happy number.

It is not a de Polignac number, because 21681670001 - 2¹⁰ = 21681668977 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21681670001.

It is not an unprimeable number, because it can be changed into a prime (21681670501) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2855456 + ... + 2863038.

It is an arithmetic number, because the mean of its divisors is an integer number (1453852800).

Almost surely, 2^21681670001 is an apocalyptic number.

It is an amenable number.

21681670001 is a deficient number, since it is larger than the sum of its proper divisors (1579974799).

21681670001 is a wasteful number, since it uses less digits than its factorization.

21681670001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9808.

The product of its (nonzero) digits is 4032, while the sum is 32.

The spelling of 21681670001 in words is "twenty-one billion, six hundred eighty-one million, six hundred seventy thousand, one".