821525421 has 8 divisors (see below), whose sum is σ = 1095636064. Its totient is φ = 547549200.

The previous prime is 821525359. The next prime is 821525437. The reversal of 821525421 is 124525128.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-821525421 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 (821525321) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18355 + ... + 44496.

It is an arithmetic number, because the mean of its divisors is an integer number (136954508).

Almost surely, 2^821525421 is an apocalyptic number.

It is an amenable number.

821525421 is a deficient number, since it is larger than the sum of its proper divisors (274110643).

821525421 is a wasteful number, since it uses less digits than its factorization.

821525421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67211.

The product of its digits is 6400, while the sum is 30.

The square root of 821525421 is about 28662.2647569936. The cubic root of 821525421 is about 936.5702007743.

The spelling of 821525421 in words is "eight hundred twenty-one million, five hundred twenty-five thousand, four hundred twenty-one".