77205649 has 4 divisors (see below), whose sum is σ = 77223664. Its totient is φ = 77187636.

The previous prime is 77205647. The next prime is 77205659. The reversal of 77205649 is 94650277.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 94650277 = 647 ⋅146291.

It is a cyclic number.

It is not a de Polignac number, because 77205649 - 2¹ = 77205647 is a prime.

It is a super-2 number, since 2×77205649² = 11921424475022402, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (77205647) 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, 1534 + ... + 12520.

It is an arithmetic number, because the mean of its divisors is an integer number (19305916).

Almost surely, 2^77205649 is an apocalyptic number.

It is an amenable number.

77205649 is a deficient number, since it is larger than the sum of its proper divisors (18015).

77205649 is a wasteful number, since it uses less digits than its factorization.

77205649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18014.

The product of its (nonzero) digits is 105840, while the sum is 40.

The square root of 77205649 is about 8786.6745131477. The cubic root of 77205649 is about 425.8104930498.

The spelling of 77205649 in words is "seventy-seven million, two hundred five thousand, six hundred forty-nine".