671522021 has 4 divisors (see below), whose sum is σ = 675641952. Its totient is φ = 667402092.

The previous prime is 671522017. The next prime is 671522023. The reversal of 671522021 is 120225176.

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 a cyclic number.

It is not a de Polignac number, because 671522021 - 2² = 671522017 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 (671522023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2059721 + ... + 2060046.

It is an arithmetic number, because the mean of its divisors is an integer number (168910488).

Almost surely, 2^671522021 is an apocalyptic number.

It is an amenable number.

671522021 is a deficient number, since it is larger than the sum of its proper divisors (4119931).

671522021 is a wasteful number, since it uses less digits than its factorization.

671522021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4119930.

The product of its (nonzero) digits is 1680, while the sum is 26.

The square root of 671522021 is about 25913.7419335765. The cubic root of 671522021 is about 875.6961082667.

Adding to 671522021 its reverse (120225176), we get a palindrome (791747197).

The spelling of 671522021 in words is "six hundred seventy-one million, five hundred twenty-two thousand, twenty-one".