721187420 has 24 divisors (see below), whose sum is σ = 1522962000. Its totient is φ = 286861952.

The previous prime is 721187393. The next prime is 721187429. The reversal of 721187420 is 24781127.

It is a happy number.

It is a super-2 number, since 2×721187420² = 1040222589532512800, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721187429) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 97145 + ... + 104304.

It is an arithmetic number, because the mean of its divisors is an integer number (63456750).

Almost surely, 2^721187420 is an apocalyptic number.

It is an amenable number.

721187420 is an abundant number, since it is smaller than the sum of its proper divisors (801774580).

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

721187420 is a wasteful number, since it uses less digits than its factorization.

721187420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 201637 (or 201635 counting only the distinct ones).

The product of its (nonzero) digits is 6272, while the sum is 32.

The square root of 721187420 is about 26854.9328801991. The cubic root of 721187420 is about 896.7733925531.

The spelling of 721187420 in words is "seven hundred twenty-one million, one hundred eighty-seven thousand, four hundred twenty".