821985573 has 4 divisors (see below), whose sum is σ = 1095980768. Its totient is φ = 547990380.

The previous prime is 821985559. The next prime is 821985587. The reversal of 821985573 is 375589128.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (821985559) and next prime (821985587).

It is not a de Polignac number, because 821985573 - 2⁴ = 821985557 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (821985503) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 136997593 + ... + 136997598.

It is an arithmetic number, because the mean of its divisors is an integer number (273995192).

Almost surely, 2^821985573 is an apocalyptic number.

It is an amenable number.

821985573 is a deficient number, since it is larger than the sum of its proper divisors (273995195).

821985573 is a wasteful number, since it uses less digits than its factorization.

821985573 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 273995194.

The product of its digits is 604800, while the sum is 48.

The square root of 821985573 is about 28670.2907728540. The cubic root of 821985573 is about 936.7450317254.

The spelling of 821985573 in words is "eight hundred twenty-one million, nine hundred eighty-five thousand, five hundred seventy-three".