664701447547421 has 16 divisors (see below), whose sum is σ = 675975655860480. Its totient is φ = 653439517908480.

The previous prime is 664701447547369. The next prime is 664701447547447. The reversal of 664701447547421 is 124745744107466.

It is a cyclic number.

It is not a de Polignac number, because 664701447547421 - 2³⁴ = 664684267678237 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 (664701447547121) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 784823840 + ... + 785670326.

It is an arithmetic number, because the mean of its divisors is an integer number (42248478491280).

Almost surely, 2^{664701447547421} is an apocalyptic number.

664701447547421 is a gapful number since it is divisible by the number (61) formed by its first and last digit.

It is an amenable number.

664701447547421 is a deficient number, since it is larger than the sum of its proper divisors (11274208313059).

664701447547421 is a wasteful number, since it uses less digits than its factorization.

664701447547421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 853724.

The product of its (nonzero) digits is 126443520, while the sum is 62.

The spelling of 664701447547421 in words is "six hundred sixty-four trillion, seven hundred one billion, four hundred forty-seven million, five hundred forty-seven thousand, four hundred twenty-one".