77021640 has 48 divisors (see below), whose sum is σ = 250321500. Its totient is φ = 20539008.

The previous prime is 77021621. The next prime is 77021647. The reversal of 77021640 is 4612077.

It can be written as a sum of positive squares in 2 ways, for example, as 76422564 + 599076 = 8742^2 + 774^2 .

It is not an unprimeable number, because it can be changed into a prime (77021647) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 106615 + ... + 107334.

Almost surely, 2^77021640 is an apocalyptic number.

It is an amenable number.

77021640 is an abundant number, since it is smaller than the sum of its proper divisors (173299860).

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

77021640 is a wasteful number, since it uses less digits than its factorization.

77021640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 213966 (or 213959 counting only the distinct ones).

The product of its (nonzero) digits is 2352, while the sum is 27.

The square root of 77021640 is about 8776.1973542076. The cubic root of 77021640 is about 425.4719371091.

The spelling of 77021640 in words is "seventy-seven million, twenty-one thousand, six hundred forty".