721465 has 8 divisors (see below), whose sum is σ = 870408. Its totient is φ = 574080.

The previous prime is 721451. The next prime is 721481. The reversal of 721465 is 564127.

It can be written as a sum of positive squares in 4 ways, for example, as 10816 + 710649 = 104^2 + 843^2 .

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

It is not a de Polignac number, because 721465 - 2⁷ = 721337 is a prime.

It is a Duffinian number.

721465 is a lucky number.

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, 1335 + ... + 1795.

It is an arithmetic number, because the mean of its divisors is an integer number (108801).

2⁷²¹⁴⁶⁵ is an apocalyptic number.

It is an amenable number.

721465 is a deficient number, since it is larger than the sum of its proper divisors (148943).

721465 is a wasteful number, since it uses less digits than its factorization.

721465 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 779.

The product of its digits is 1680, while the sum is 25.

The square root of 721465 is about 849.3909582754. The cubic root of 721465 is about 89.6888431733.

The spelling of 721465 in words is "seven hundred twenty-one thousand, four hundred sixty-five".