671551421 has 4 divisors (see below), whose sum is σ = 671963292. Its totient is φ = 671139552.

The previous prime is 671551417. The next prime is 671551469. The reversal of 671551421 is 124155176.

671551421 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 155625625 + 515925796 = 12475^2 + 22714^2 .

It is a cyclic number.

It is not a de Polignac number, because 671551421 - 2² = 671551417 is a prime.

It is a super-2 number, since 2×671551421² = 901962622094238482, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (671551721) 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, 203480 + ... + 206753.

It is an arithmetic number, because the mean of its divisors is an integer number (167990823).

Almost surely, 2^671551421 is an apocalyptic number.

It is an amenable number.

671551421 is a deficient number, since it is larger than the sum of its proper divisors (411871).

671551421 is a wasteful number, since it uses less digits than its factorization.

671551421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 411870.

The product of its digits is 8400, while the sum is 32.

The square root of 671551421 is about 25914.3091939569. The cubic root of 671551421 is about 875.7088877383.

The spelling of 671551421 in words is "six hundred seventy-one million, five hundred fifty-one thousand, four hundred twenty-one".