721640754 has 48 divisors (see below), whose sum is σ = 1653410304. Its totient is φ = 227102400.

The previous prime is 721640753. The next prime is 721640771. The reversal of 721640754 is 457046127.

721640754 is a `hidden beast` number, since 7 + 2 + 1 + 640 + 7 + 5 + 4 = 666.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (721640753) 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, 7107 + ... + 38649.

It is an arithmetic number, because the mean of its divisors is an integer number (34446048).

Almost surely, 2^721640754 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 721640754, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (826705152).

721640754 is an abundant number, since it is smaller than the sum of its proper divisors (931769550).

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

721640754 is a wasteful number, since it uses less digits than its factorization.

721640754 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31623 (or 31620 counting only the distinct ones).

The product of its (nonzero) digits is 47040, while the sum is 36.

The square root of 721640754 is about 26863.3719774715. The cubic root of 721640754 is about 896.9612552848.

The spelling of 721640754 in words is "seven hundred twenty-one million, six hundred forty thousand, seven hundred fifty-four".