721767316025551 has 4 divisors (see below), whose sum is σ = 759755069500600. Its totient is φ = 683779562550504.

The previous prime is 721767316025507. The next prime is 721767316025621. The reversal of 721767316025551 is 155520613767127.

721767316025551 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 721767316025551 - 2¹⁵ = 721767315992783 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721767316725551) 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, 18993876737496 + ... + 18993876737533.

It is an arithmetic number, because the mean of its divisors is an integer number (189938767375150).

Almost surely, 2^{721767316025551} is an apocalyptic number.

721767316025551 is a deficient number, since it is larger than the sum of its proper divisors (37987753475049).

721767316025551 is a wasteful number, since it uses less digits than its factorization.

721767316025551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37987753475048.

The product of its (nonzero) digits is 18522000, while the sum is 58.

The spelling of 721767316025551 in words is "seven hundred twenty-one trillion, seven hundred sixty-seven billion, three hundred sixteen million, twenty-five thousand, five hundred fifty-one".