721404536 has 8 divisors (see below), whose sum is σ = 1352633520. Its totient is φ = 360702264.

The previous prime is 721404533. The next prime is 721404539. The reversal of 721404536 is 635404127.

It is an interprime number because it is at equal distance from previous prime (721404533) and next prime (721404539).

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

It is a super-2 number, since 2×721404536² = 1040849009122750592, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721404533) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45087776 + ... + 45087791.

It is an arithmetic number, because the mean of its divisors is an integer number (169079190).

Almost surely, 2^721404536 is an apocalyptic number.

It is an amenable number.

721404536 is a deficient number, since it is larger than the sum of its proper divisors (631228984).

721404536 is a wasteful number, since it uses less digits than its factorization.

721404536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90175573 (or 90175569 counting only the distinct ones).

The product of its (nonzero) digits is 20160, while the sum is 32.

The square root of 721404536 is about 26858.9749618261. The cubic root of 721404536 is about 896.8633757812.

The spelling of 721404536 in words is "seven hundred twenty-one million, four hundred four thousand, five hundred thirty-six".