77644150609 has 27 divisors (see below), whose sum is σ = 84961344657. Its totient is φ = 70941297024.

The previous prime is 77644150567. The next prime is 77644150631. The reversal of 77644150609 is 90605144677.

The square root of 77644150609 is 278647.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 36117862209 + 41526288400 = 190047^2 + 203780^2 .

It is not a de Polignac number, because 77644150609 - 2¹⁹ = 77643626321 is a prime.

It is a super-2 number, since 2×77644150609² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (77644150679) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 175268742 + ... + 175269184.

Almost surely, 2^77644150609 is an apocalyptic number.

77644150609 is the 278647-th square number.

77644150609 is the 139324-th centered octagonal number.

It is an amenable number.

77644150609 is a deficient number, since it is larger than the sum of its proper divisors (7317194048).

77644150609 is an frugal number, since it uses more digits than its factorization.

77644150609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 994 (or 497 counting only the distinct ones).

The product of its (nonzero) digits is 1270080, while the sum is 49.

Multiplying 77644150609 by its sum of digits (49), we get a square (3804563379841 = 1950529²).

The spelling of 77644150609 in words is "seventy-seven billion, six hundred forty-four million, one hundred fifty thousand, six hundred nine".