77698775025 has 27 divisors (see below), whose sum is σ = 139174628619. Its totient is φ = 41437116720.

The previous prime is 77698774973. The next prime is 77698775029. The reversal of 77698775025 is 52057789677.

The square root of 77698775025 is 278745.

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

It can be written as a sum of positive squares in only one way, i.e., 27971559009 + 49727216016 = 167247^2 + 222996^2 .

It is not a de Polignac number, because 77698775025 - 2⁷ = 77698774897 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (77698775029) 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, 4171884 + ... + 4190466.

Almost surely, 2^77698775025 is an apocalyptic number.

77698775025 is a gapful number since it is divisible by the number (75) formed by its first and last digit.

77698775025 is the 278745-th square number.

77698775025 is the 139373-rd centered octagonal number.

It is an amenable number.

77698775025 is a deficient number, since it is larger than the sum of its proper divisors (61475853594).

77698775025 is an frugal number, since it uses more digits than its factorization.

77698775025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37182 (or 18591 counting only the distinct ones).

The product of its (nonzero) digits is 51861600, while the sum is 63.

The spelling of 77698775025 in words is "seventy-seven billion, six hundred ninety-eight million, seven hundred seventy-five thousand, twenty-five".