21199707678 has 16 divisors (see below), whose sum is σ = 43767138816. Its totient is φ = 6838615320.

The previous prime is 21199707677. The next prime is 21199707689. The reversal of 21199707678 is 87670799112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21199707677) 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, 56988276 + ... + 56988647.

It is an arithmetic number, because the mean of its divisors is an integer number (2735446176).

Almost surely, 2^21199707678 is an apocalyptic number.

21199707678 is an abundant number, since it is smaller than the sum of its proper divisors (22567431138).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21199707678 is a wasteful number, since it uses less digits than its factorization.

21199707678 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 113976959.

The product of its (nonzero) digits is 2667168, while the sum is 57.

The spelling of 21199707678 in words is "twenty-one billion, one hundred ninety-nine million, seven hundred seven thousand, six hundred seventy-eight".