721477 has 4 divisors (see below), whose sum is σ = 739116. Its totient is φ = 703840.

The previous prime is 721451. The next prime is 721481. The reversal of 721477 is 774127.

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 25921 + 695556 = 161^2 + 834^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-721477 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 (721177) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8758 + ... + 8839.

It is an arithmetic number, because the mean of its divisors is an integer number (184779).

2⁷²¹⁴⁷⁷ is an apocalyptic number.

It is an amenable number.

721477 is a deficient number, since it is larger than the sum of its proper divisors (17639).

721477 is a wasteful number, since it uses less digits than its factorization.

721477 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17638.

The product of its digits is 2744, while the sum is 28.

The square root of 721477 is about 849.3980221310. The cubic root of 721477 is about 89.6893404301.

Subtracting 721477 from its reverse (774127), we obtain a triangular number (52650 = T₃₂₄).

The spelling of 721477 in words is "seven hundred twenty-one thousand, four hundred seventy-seven", and thus it is an iban number.