721624 has 8 divisors (see below), whose sum is σ = 1353060. Its totient is φ = 360808.

The previous prime is 721621. The next prime is 721631. The reversal of 721624 is 426127.

It is a tau number, because it is divible by the number of its divisors (8).

It is a junction number, because it is equal to n+sod(n) for n = 721595 and 721604.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45094 + ... + 45109.

2⁷²¹⁶²⁴ is an apocalyptic number.

It is an amenable number.

721624 is a deficient number, since it is larger than the sum of its proper divisors (631436).

721624 is a wasteful number, since it uses less digits than its factorization.

721624 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90209 (or 90205 counting only the distinct ones).

The product of its digits is 672, while the sum is 22.

The square root of 721624 is about 849.4845495946. The cubic root of 721624 is about 89.6954313786.

The spelling of 721624 in words is "seven hundred twenty-one thousand, six hundred twenty-four".