7278221620 has 12 divisors (see below), whose sum is σ = 15284265444. Its totient is φ = 2911288640.

The previous prime is 7278221617. The next prime is 7278221627. The reversal of 7278221620 is 261228727.

It can be written as a sum of positive squares in 2 ways, for example, as 3433725604 + 3844496016 = 58598^2 + 62004^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 7278221620.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7278221627) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 181955521 + ... + 181955560.

It is an arithmetic number, because the mean of its divisors is an integer number (1273688787).

Almost surely, 2^7278221620 is an apocalyptic number.

It is an amenable number.

7278221620 is an abundant number, since it is smaller than the sum of its proper divisors (8006043824).

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

7278221620 is a wasteful number, since it uses less digits than its factorization.

7278221620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 363911090 (or 363911088 counting only the distinct ones).

The product of its (nonzero) digits is 37632, while the sum is 37.

The square root of 7278221620 is about 85312.4939267397. The cubic root of 7278221620 is about 1937.9463885516.

The spelling of 7278221620 in words is "seven billion, two hundred seventy-eight million, two hundred twenty-one thousand, six hundred twenty".