3621649978 has 16 divisors (see below), whose sum is σ = 5950379880. Its totient is φ = 1645536256.

The previous prime is 3621649963. The next prime is 3621649979. The reversal of 3621649978 is 8799461263.

It can be written as a sum of positive squares in 4 ways, for example, as 2980395649 + 641254329 = 54593^2 + 25323^2 .

It is not an unprimeable number, because it can be changed into a prime (3621649979) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1835551 + ... + 1837522.

Almost surely, 2^3621649978 is an apocalyptic number.

3621649978 is a deficient number, since it is larger than the sum of its proper divisors (2328729902).

3621649978 is a wasteful number, since it uses less digits than its factorization.

3621649978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3673121.

The product of its digits is 3919104, while the sum is 55.

The square root of 3621649978 is about 60180.1460450205. The cubic root of 3621649978 is about 1535.6850564697.

The spelling of 3621649978 in words is "three billion, six hundred twenty-one million, six hundred forty-nine thousand, nine hundred seventy-eight".