671624921 has 4 divisors (see below), whose sum is σ = 732681744. Its totient is φ = 610568100.

The previous prime is 671624917. The next prime is 671624927. The reversal of 671624921 is 129426176.

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 671624921 - 2² = 671624917 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (671624927) 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, 30528395 + ... + 30528416.

It is an arithmetic number, because the mean of its divisors is an integer number (183170436).

Almost surely, 2^671624921 is an apocalyptic number.

It is an amenable number.

671624921 is a deficient number, since it is larger than the sum of its proper divisors (61056823).

671624921 is a wasteful number, since it uses less digits than its factorization.

671624921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 61056822.

The product of its digits is 36288, while the sum is 38.

The square root of 671624921 is about 25915.7272905855. The cubic root of 671624921 is about 875.7408347857.

The spelling of 671624921 in words is "six hundred seventy-one million, six hundred twenty-four thousand, nine hundred twenty-one".