77781097 has 4 divisors (see below), whose sum is σ = 78276676. Its totient is φ = 77285520.

The previous prime is 77781073. The next prime is 77781107. The reversal of 77781097 is 79018777.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 45643536 + 32137561 = 6756^2 + 5669^2 .

It is a cyclic number.

It is not a de Polignac number, because 77781097 - 2¹⁵ = 77748329 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (77781017) 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, 247554 + ... + 247867.

It is an arithmetic number, because the mean of its divisors is an integer number (19569169).

Almost surely, 2^77781097 is an apocalyptic number.

It is an amenable number.

77781097 is a deficient number, since it is larger than the sum of its proper divisors (495579).

77781097 is a wasteful number, since it uses less digits than its factorization.

77781097 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 495578.

The product of its (nonzero) digits is 172872, while the sum is 46.

The square root of 77781097 is about 8819.3592170860. The cubic root of 77781097 is about 426.8657937573.

The spelling of 77781097 in words is "seventy-seven million, seven hundred eighty-one thousand, ninety-seven".