721949536 has 144 divisors (see below), whose sum is σ = 1899495360. Its totient is φ = 266353920.

The previous prime is 721949533. The next prime is 721949537. The reversal of 721949536 is 635949127.

It is a happy number.

It is a super-2 number, since 2×721949536² = 1042422265061230592, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721949533) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 326611 + ... + 328813.

It is an arithmetic number, because the mean of its divisors is an integer number (13190940).

Almost surely, 2^721949536 is an apocalyptic number.

721949536 is a gapful number since it is divisible by the number (76) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 721949536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (949747680).

721949536 is an abundant number, since it is smaller than the sum of its proper divisors (1177545824).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

721949536 is a wasteful number, since it uses less digits than its factorization.

721949536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2257 (or 2242 counting only the distinct ones).

The product of its digits is 408240, while the sum is 46.

The square root of 721949536 is about 26869.1186308744. The cubic root of 721949536 is about 897.0891702687.

The spelling of 721949536 in words is "seven hundred twenty-one million, nine hundred forty-nine thousand, five hundred thirty-six".