7916278221 has 6 divisors (see below), whose sum is σ = 11434624110. Its totient is φ = 5277518808.

The previous prime is 7916278189. The next prime is 7916278231. The reversal of 7916278221 is 1228726197.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 4848336900 + 3067941321 = 69630^2 + 55389^2 .

It is not a de Polignac number, because 7916278221 - 2⁵ = 7916278189 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7916278231) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 439793226 + ... + 439793243.

It is an arithmetic number, because the mean of its divisors is an integer number (1905770685).

Almost surely, 2^7916278221 is an apocalyptic number.

It is an amenable number.

7916278221 is a deficient number, since it is larger than the sum of its proper divisors (3518345889).

7916278221 is a wasteful number, since it uses less digits than its factorization.

7916278221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 879586475 (or 879586472 counting only the distinct ones).

The product of its digits is 169344, while the sum is 45.

The square root of 7916278221 is about 88973.4691972837. The cubic root of 7916278221 is about 1992.9987046140.

The spelling of 7916278221 in words is "seven billion, nine hundred sixteen million, two hundred seventy-eight thousand, two hundred twenty-one".