64144431561661 has 16 divisors (see below), whose sum is σ = 70804129131648. Its totient is φ = 57626800128000.

The previous prime is 64144431561589. The next prime is 64144431561667. The reversal of 64144431561661 is 16616513444146.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-64144431561661 is a prime.

It is a super-2 number, since 2×64144431561661² (a number of 28 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 64144431561599 and 64144431561608.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64144431561667) 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, 99725956 + ... + 100367101.

It is an arithmetic number, because the mean of its divisors is an integer number (4425258070728).

Almost surely, 2^{64144431561661} is an apocalyptic number.

It is an amenable number.

64144431561661 is a deficient number, since it is larger than the sum of its proper divisors (6659697569987).

64144431561661 is a wasteful number, since it uses less digits than its factorization.

64144431561661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 200093412.

The product of its digits is 4976640, while the sum is 52.

The spelling of 64144431561661 in words is "sixty-four trillion, one hundred forty-four billion, four hundred thirty-one million, five hundred sixty-one thousand, six hundred sixty-one".