721409587 has 4 divisors (see below), whose sum is σ = 744680896. Its totient is φ = 698138280.

The previous prime is 721409573. The next prime is 721409617. The reversal of 721409587 is 785904127.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 785904127 = 383 ⋅2051969.

It is a cyclic number.

It is not a de Polignac number, because 721409587 - 2⁷ = 721409459 is a prime.

It is a super-3 number, since 3×721409587³ (a number of 28 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (721409527) 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, 11635608 + ... + 11635669.

It is an arithmetic number, because the mean of its divisors is an integer number (186170224).

Almost surely, 2^721409587 is an apocalyptic number.

721409587 is a deficient number, since it is larger than the sum of its proper divisors (23271309).

721409587 is a wasteful number, since it uses less digits than its factorization.

721409587 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23271308.

The product of its (nonzero) digits is 141120, while the sum is 43.

The square root of 721409587 is about 26859.0689898217. The cubic root of 721409587 is about 896.8654689417.

The spelling of 721409587 in words is "seven hundred twenty-one million, four hundred nine thousand, five hundred eighty-seven".