721887 has 8 divisors (see below), whose sum is σ = 986160. Its totient is φ = 469440.

The previous prime is 721883. The next prime is 721891. The reversal of 721887 is 788127.

It is an interprime number because it is at equal distance from previous prime (721883) and next prime (721891).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 721887 - 2² = 721883 is a prime.

It is a super-3 number, since 3×721887³ = 1128571081140633309, which contains 333 as substring. Note that it is a super-d number also for d = 2.

721887 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721883) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2812 + ... + 3057.

It is an arithmetic number, because the mean of its divisors is an integer number (123270).

2⁷²¹⁸⁸⁷ is an apocalyptic number.

721887 is a deficient number, since it is larger than the sum of its proper divisors (264273).

721887 is a wasteful number, since it uses less digits than its factorization.

721887 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5913.

The product of its digits is 6272, while the sum is 33.

The square root of 721887 is about 849.6393352476. The cubic root of 721887 is about 89.7063267263.

The spelling of 721887 in words is "seven hundred twenty-one thousand, eight hundred eighty-seven".