16619891661 has 16 divisors (see below), whose sum is σ = 25039387200. Its totient is φ = 10892131344.

The previous prime is 16619891621. The next prime is 16619891663.

16619891661 is a `hidden beast` number, since 1 + 6 + 619 + 8 + 9 + 16 + 6 + 1 = 666.

16619891661 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 16619891661 - 2²¹ = 16617794509 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 16619891598 and 16619891607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16619891663) 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, 5214946 + ... + 5218131.

It is an arithmetic number, because the mean of its divisors is an integer number (1564961700).

Almost surely, 2^16619891661 is an apocalyptic number.

It is an amenable number.

16619891661 is a deficient number, since it is larger than the sum of its proper divisors (8419495539).

16619891661 is a wasteful number, since it uses less digits than its factorization.

16619891661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10433145 (or 10433139 counting only the distinct ones).

The product of its digits is 839808, while the sum is 54.

The spelling of 16619891661 in words is "sixteen billion, six hundred nineteen million, eight hundred ninety-one thousand, six hundred sixty-one".