721425840 has 40 divisors (see below), whose sum is σ = 2236420848. Its totient is φ = 192380160.

The previous prime is 721425829. The next prime is 721425851. The reversal of 721425840 is 48524127.

It is an interprime number because it is at equal distance from previous prime (721425829) and next prime (721425851).

It is a tau number, because it is divible by the number of its divisors (40).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1502731 + ... + 1503210.

Almost surely, 2^721425840 is an apocalyptic number.

It is an amenable number.

721425840 is an abundant number, since it is smaller than the sum of its proper divisors (1514995008).

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

721425840 is a wasteful number, since it uses less digits than its factorization.

721425840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3005957 (or 3005951 counting only the distinct ones).

The product of its (nonzero) digits is 17920, while the sum is 33.

The square root of 721425840 is about 26859.3715488654. The cubic root of 721425840 is about 896.8722042024.

Adding to 721425840 its reverse (48524127), we get a palindrome (769949967).

The spelling of 721425840 in words is "seven hundred twenty-one million, four hundred twenty-five thousand, eight hundred forty".