721156461409 has 4 divisors (see below), whose sum is σ = 721819899904. Its totient is φ = 720493022916.

The previous prime is 721156461341. The next prime is 721156461461. The reversal of 721156461409 is 904164651127.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 721156461409 - 2⁷ = 721156461281 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (721156461479) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 331717617 + ... + 331719790.

It is an arithmetic number, because the mean of its divisors is an integer number (180454974976).

Almost surely, 2^721156461409 is an apocalyptic number.

It is an amenable number.

721156461409 is a deficient number, since it is larger than the sum of its proper divisors (663438495).

721156461409 is a wasteful number, since it uses less digits than its factorization.

721156461409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 663438494.

The product of its (nonzero) digits is 362880, while the sum is 46.

The spelling of 721156461409 in words is "seven hundred twenty-one billion, one hundred fifty-six million, four hundred sixty-one thousand, four hundred nine".