77628709 has 4 divisors (see below), whose sum is σ = 77647360. Its totient is φ = 77610060.

The previous prime is 77628697. The next prime is 77628767. The reversal of 77628709 is 90782677.

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: 90782677 = 9043 ⋅10039.

It is a cyclic number.

It is not a de Polignac number, because 77628709 - 2²¹ = 75531557 is a prime.

It is a super-2 number, since 2×77628709² = 12052432922013362, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77628209) 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, 82 + ... + 12460.

It is an arithmetic number, because the mean of its divisors is an integer number (19411840).

Almost surely, 2^77628709 is an apocalyptic number.

It is an amenable number.

77628709 is a deficient number, since it is larger than the sum of its proper divisors (18651).

77628709 is a wasteful number, since it uses less digits than its factorization.

77628709 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18650.

The product of its (nonzero) digits is 296352, while the sum is 46.

The square root of 77628709 is about 8810.7155782036. The cubic root of 77628709 is about 426.5868410097.

It can be divided in two parts, 7762 and 8709, that added together give a triangular number (16471 = T₁₈₁).

The spelling of 77628709 in words is "seventy-seven million, six hundred twenty-eight thousand, seven hundred nine".