16001601561 has 72 divisors (see below), whose sum is σ = 26579349888. Its totient is φ = 9252144000.

The previous prime is 16001601559. The next prime is 16001601569. The reversal of 16001601561 is 16510610061.

16001601561 is a `hidden beast` number, since 1 + 6 + 0 + 0 + 1 + 601 + 56 + 1 = 666.

It is not a de Polignac number, because 16001601561 - 2¹ = 16001601559 is a prime.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (16001601569) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 15052716 + ... + 15053778.

Almost surely, 2^16001601561 is an apocalyptic number.

16001601561 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

16001601561 is a deficient number, since it is larger than the sum of its proper divisors (10577748327).

16001601561 is a wasteful number, since it uses less digits than its factorization.

16001601561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1715 (or 1701 counting only the distinct ones).

The product of its (nonzero) digits is 1080, while the sum is 27.

The spelling of 16001601561 in words is "sixteen billion, one million, six hundred one thousand, five hundred sixty-one".