850155917521 has 3 divisors (see below), whose sum is σ = 850156839561. Its totient is φ = 850154995482.

The previous prime is 850155917459. The next prime is 850155917531. The reversal of 850155917521 is 125719551058.

It is a happy number.

The square root of 850155917521 is 922039.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 850155917521 - 2²³ = 850147528913 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (850155917531) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 461020 + ... + 1383058.

It is an arithmetic number, because the mean of its divisors is an integer number (283385613187).

Almost surely, 2^850155917521 is an apocalyptic number.

850155917521 is the 922039-th square number.

850155917521 is the 461020-th centered octagonal number.

It is an amenable number.

850155917521 is a deficient number, since it is larger than the sum of its proper divisors (922040).

850155917521 is an frugal number, since it uses more digits than its factorization.

850155917521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1844078 (or 922039 counting only the distinct ones).

The product of its (nonzero) digits is 630000, while the sum is 49.

Multiplying 850155917521 by its sum of digits (49), we get a square (41657639958529 = 6454273²).

The spelling of 850155917521 in words is "eight hundred fifty billion, one hundred fifty-five million, nine hundred seventeen thousand, five hundred twenty-one".