61787381645025 has 81 divisors (see below), whose sum is σ = 111447477530571. Its totient is φ = 32722800497280.

The previous prime is 61787381645023. The next prime is 61787381645039. The reversal of 61787381645025 is 52054618378716.

It is a happy number.

The square root of 61787381645025 is 7860495.

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

61787381645025 is a `hidden beast` number, since 6 + 1 + 7 + 87 + 3 + 81 + 6 + 450 + 25 = 666.

It can be written as a sum of positive squares in 13 ways, for example, as 30599937221841 + 31187444423184 = 5531721^2 + 5584572^2 .

It is not a de Polignac number, because 61787381645025 - 2¹ = 61787381645023 is a prime.

It is not an unprimeable number, because it can be changed into a prime (61787381645023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 17568204567 + ... + 17568208083.

Almost surely, 2^{61787381645025} is an apocalyptic number.

61787381645025 is the 7860495-th square number.

61787381645025 is the 3930248-th centered octagonal number.

It is an amenable number.

61787381645025 is a deficient number, since it is larger than the sum of its proper divisors (49660095885546).

61787381645025 is an frugal number, since it uses more digits than its factorization.

61787381645025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7348 (or 3674 counting only the distinct ones).

The product of its (nonzero) digits is 67737600, while the sum is 63.

The spelling of 61787381645025 in words is "sixty-one trillion, seven hundred eighty-seven billion, three hundred eighty-one million, six hundred forty-five thousand, twenty-five".