817521012 has 252 divisors, whose sum is σ = 2702700448. Its totient is φ = 211701600.

The previous prime is 817520989. The next prime is 817521013. The reversal of 817521012 is 210125718.

It is a tau number, because it is divible by the number of its divisors (252).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (817521013) by changing a digit.

It is a polite number, since it can be written in 83 ways as a sum of consecutive naturals, for example, 2469687 + ... + 2470017.

Almost surely, 2^817521012 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 817521012, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1351350224).

817521012 is an abundant number, since it is smaller than the sum of its proper divisors (1885179436).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

817521012 is a wasteful number, since it uses less digits than its factorization.

817521012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 382 (or 354 counting only the distinct ones).

The product of its (nonzero) digits is 1120, while the sum is 27.

The square root of 817521012 is about 28592.3243546236. The cubic root of 817521012 is about 935.0459954305.

The spelling of 817521012 in words is "eight hundred seventeen million, five hundred twenty-one thousand, twelve".