721349820 has 192 divisors, whose sum is σ = 2382105600. Its totient is φ = 180714240.

The previous prime is 721349803. The next prime is 721349861. The reversal of 721349820 is 28943127.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1713210 + ... + 1713630.

It is an arithmetic number, because the mean of its divisors is an integer number (12406800).

Almost surely, 2^721349820 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 721349820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1191052800).

721349820 is an abundant number, since it is smaller than the sum of its proper divisors (1660755780).

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

721349820 is a wasteful number, since it uses less digits than its factorization.

721349820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 625 (or 617 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 36.

The square root of 721349820 is about 26857.9563630593. The cubic root of 721349820 is about 896.8407005624.

The spelling of 721349820 in words is "seven hundred twenty-one million, three hundred forty-nine thousand, eight hundred twenty".