85725398521 has 27 divisors (see below), whose sum is σ = 100749875247. Its totient is φ = 72728787600.

The previous prime is 85725398519. The next prime is 85725398567. The reversal of 85725398521 is 12589352758.

The square root of 85725398521 is 292789.

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., 14775618025 + 70949780496 = 121555^2 + 266364^2 .

It is not a de Polignac number, because 85725398521 - 2¹ = 85725398519 is a prime.

It is not an unprimeable number, because it can be changed into a prime (85725398581) 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, 309477835 + ... + 309478111.

It is an arithmetic number, because the mean of its divisors is an integer number (3731476861).

Almost surely, 2^85725398521 is an apocalyptic number.

85725398521 is the 292789-th square number.

85725398521 is the 146395-th centered octagonal number.

It is an amenable number.

85725398521 is a deficient number, since it is larger than the sum of its proper divisors (15024476726).

85725398521 is an frugal number, since it uses more digits than its factorization.

85725398521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 870 (or 435 counting only the distinct ones).

The product of its digits is 6048000, while the sum is 55.

The spelling of 85725398521 in words is "eighty-five billion, seven hundred twenty-five million, three hundred ninety-eight thousand, five hundred twenty-one".