721540032 has 28 divisors (see below), whose sum is σ = 1909075176. Its totient is φ = 240513280.

The previous prime is 721540019. The next prime is 721540037. The reversal of 721540032 is 230045127.

It is a super-2 number, since 2×721540032² = 1041240035557122048, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a junction number, because it is equal to n+sod(n) for n = 721539984 and 721540011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721540037) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1878819 + ... + 1879202.

Almost surely, 2^721540032 is an apocalyptic number.

It is an amenable number.

721540032 is an abundant number, since it is smaller than the sum of its proper divisors (1187535144).

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

721540032 is a wasteful number, since it uses less digits than its factorization.

721540032 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3758036 (or 3758026 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 24.

The square root of 721540032 is about 26861.4972032461. The cubic root of 721540032 is about 896.9195226385.

Adding to 721540032 its reverse (230045127), we get a palindrome (951585159).

The spelling of 721540032 in words is "seven hundred twenty-one million, five hundred forty thousand, thirty-two".