16381752661 has 4 divisors (see below), whose sum is σ = 16383245292. Its totient is φ = 16380260032.

The previous prime is 16381752643. The next prime is 16381752677. The reversal of 16381752661 is 16625718361.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 11466340561 + 4915412100 = 107081^2 + 70110^2 .

It is a cyclic number.

It is not a de Polignac number, because 16381752661 - 2¹⁷ = 16381621589 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 (16381752061) 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, 729730 + ... + 751843.

It is an arithmetic number, because the mean of its divisors is an integer number (4095811323).

Almost surely, 2^16381752661 is an apocalyptic number.

It is an amenable number.

16381752661 is a deficient number, since it is larger than the sum of its proper divisors (1492631).

16381752661 is a wasteful number, since it uses less digits than its factorization.

16381752661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1492630.

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

The spelling of 16381752661 in words is "sixteen billion, three hundred eighty-one million, seven hundred fifty-two thousand, six hundred sixty-one".