6409763721 has 9 divisors (see below), whose sum is σ = 9258894541. Its totient is φ = 4273015692.

The previous prime is 6409763719. The next prime is 6409763747. The reversal of 6409763721 is 1273679046.

The square root of 6409763721 is 80061.

It is a perfect power (a square), and thus also a powerful number.

6409763721 is a `hidden beast` number, since 6 + 4 + 0 + 9 + 7 + 637 + 2 + 1 = 666.

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 6409763721 - 2¹ = 6409763719 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6409763761) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 226840 + ... + 253526.

Almost surely, 2^6409763721 is an apocalyptic number.

6409763721 is the 80061-st square number.

6409763721 is the 40031-st centered octagonal number.

It is an amenable number.

6409763721 is a deficient number, since it is larger than the sum of its proper divisors (2849130820).

6409763721 is an frugal number, since it uses more digits than its factorization.

6409763721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53380 (or 26690 counting only the distinct ones).

The product of its (nonzero) digits is 381024, while the sum is 45.

The cubic root of 6409763721 is about 1857.5792032753.

The spelling of 6409763721 in words is "six billion, four hundred nine million, seven hundred sixty-three thousand, seven hundred twenty-one".