6999537978 has 24 divisors (see below), whose sum is σ = 15168628800. Its totient is φ = 2332723464.

The previous prime is 6999537949. The next prime is 6999538031. The reversal of 6999537978 is 8797359996.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 64113 + ... + 134571.

It is an arithmetic number, because the mean of its divisors is an integer number (632026200).

Almost surely, 2^6999537978 is an apocalyptic number.

6999537978 is an abundant number, since it is smaller than the sum of its proper divisors (8169090822).

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

6999537978 is a wasteful number, since it uses less digits than its factorization.

6999537978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75986 (or 75983 counting only the distinct ones).

The product of its digits is 231472080, while the sum is 72.

The square root of 6999537978 is about 83663.2414982829. The cubic root of 6999537978 is about 1912.8890953564.

The spelling of 6999537978 in words is "six billion, nine hundred ninety-nine million, five hundred thirty-seven thousand, nine hundred seventy-eight".