78206919025 has 9 divisors (see below), whose sum is σ = 96978313483. Its totient is φ = 62564416600.

The previous prime is 78206919001. The next prime is 78206919041. The reversal of 78206919025 is 52091960287.

The square root of 78206919025 is 279655.

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., 28154490849 + 50052428176 = 167793^2 + 223724^2 .

It is not a de Polignac number, because 78206919025 - 2²⁵ = 78173364593 is a prime.

It is a super-2 number, since 2×78206919025² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 78206919025.

It is an unprimeable number.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 1370310 + ... + 1426240.

Almost surely, 2^78206919025 is an apocalyptic number.

78206919025 is the 279655-th square number.

78206919025 is the 139828-th centered octagonal number.

It is an amenable number.

78206919025 is a deficient number, since it is larger than the sum of its proper divisors (18771394458).

78206919025 is an frugal number, since it uses more digits than its factorization.

78206919025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 111872 (or 55936 counting only the distinct ones).

The product of its (nonzero) digits is 544320, while the sum is 49.

Multiplying 78206919025 by its sum of digits (49), we get a square (3832139032225 = 1957585²).

The spelling of 78206919025 in words is "seventy-eight billion, two hundred six million, nine hundred nineteen thousand, twenty-five".