825457621565 has 8 divisors (see below), whose sum is σ = 1009238752728. Its totient is φ = 647906359360.

The previous prime is 825457621529. The next prime is 825457621579. The reversal of 825457621565 is 565126754528.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 116672114329 + 708785507236 = 341573^2 + 841894^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 825457621565 - 2⁶ = 825457621501 is a prime.

It is a super-4 number, since 4×825457621565⁴ (a number of 49 digits) contains 4444 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 825457621565.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1557466946 + ... + 1557467475.

It is an arithmetic number, because the mean of its divisors is an integer number (126154844091).

Almost surely, 2^825457621565 is an apocalyptic number.

It is an amenable number.

825457621565 is a deficient number, since it is larger than the sum of its proper divisors (183781131163).

825457621565 is a wasteful number, since it uses less digits than its factorization.

825457621565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3114934479.

The product of its digits is 20160000, while the sum is 56.

The spelling of 825457621565 in words is "eight hundred twenty-five billion, four hundred fifty-seven million, six hundred twenty-one thousand, five hundred sixty-five".