672633721 has 2 divisors, whose sum is σ = 672633722. Its totient is φ = 672633720.

The previous prime is 672633719. The next prime is 672633727. The reversal of 672633721 is 127336276.

672633721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 455395600 + 217238121 = 21340^2 + 14739^2 .

It is a cyclic number.

It is not a de Polignac number, because 672633721 - 2¹ = 672633719 is a prime.

It is a super-2 number, since 2×672633721² = 904872245252611682, which contains 22 as substring.

Together with 672633719, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (672633727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 336316860 + 336316861.

It is an arithmetic number, because the mean of its divisors is an integer number (336316861).

Almost surely, 2^672633721 is an apocalyptic number.

It is an amenable number.

672633721 is a deficient number, since it is larger than the sum of its proper divisors (1).

672633721 is an equidigital number, since it uses as much as digits as its factorization.

672633721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 63504, while the sum is 37.

The square root of 672633721 is about 25935.1830724211. The cubic root of 672633721 is about 876.1790781038.

Adding to 672633721 its reverse (127336276), we get a palindrome (799969997).

The spelling of 672633721 in words is "six hundred seventy-two million, six hundred thirty-three thousand, seven hundred twenty-one".