821522025 has 72 divisors (see below), whose sum is σ = 1564803864. Its totient is φ = 410572800.

The previous prime is 821522021. The next prime is 821522047. The reversal of 821522025 is 520225128.

It can be written as a sum of positive squares in 12 ways, for example, as 97535376 + 723986649 = 9876^2 + 26907^2 .

It is not a de Polignac number, because 821522025 - 2² = 821522021 is a prime.

It is a super-3 number, since 3×821522025³ (a number of 28 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 821522025.

It is not an unprimeable number, because it can be changed into a prime (821522021) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 1518255 + ... + 1518795.

It is an arithmetic number, because the mean of its divisors is an integer number (21733387).

Almost surely, 2^821522025 is an apocalyptic number.

821522025 is a gapful number since it is divisible by the number (85) formed by its first and last digit.

It is an amenable number.

821522025 is a deficient number, since it is larger than the sum of its proper divisors (743281839).

821522025 is a wasteful number, since it uses less digits than its factorization.

821522025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 971 (or 963 counting only the distinct ones).

The product of its (nonzero) digits is 3200, while the sum is 27.

The square root of 821522025 is about 28662.2055152774. The cubic root of 821522025 is about 936.5689102495.

The spelling of 821522025 in words is "eight hundred twenty-one million, five hundred twenty-two thousand, twenty-five".