16235601561 has 9 divisors (see below), whose sum is σ = 23451976639. Its totient is φ = 10823479536.

The previous prime is 16235601523. The next prime is 16235601563. The reversal of 16235601561 is 16510653261.

The square root of 16235601561 is 127419.

It is a perfect power (a square), and thus also a powerful number.

16235601561 is a `hidden beast` number, since 1 + 6 + 2 + 35 + 60 + 1 + 561 = 666.

It can be written as a sum of positive squares in only one way, i.e., 2720144025 + 13515457536 = 52155^2 + 116256^2 .

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 16235601561 - 2²¹ = 16233504409 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16235601563) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 361021 + ... + 403493.

Almost surely, 2^16235601561 is an apocalyptic number.

16235601561 is the 127419-th square number.

16235601561 is the 63710-th centered octagonal number.

It is an amenable number.

16235601561 is a deficient number, since it is larger than the sum of its proper divisors (7216375078).

16235601561 is an frugal number, since it uses more digits than its factorization.

16235601561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84952 (or 42476 counting only the distinct ones).

The product of its (nonzero) digits is 32400, while the sum is 36.

Multiplying 16235601561 by its sum of digits (36), we get a square (584481656196 = 764514²).

Multiplying 16235601561 by its product of nonzero digits (32400), we get a square (526033490576400 = 22935420²).

It can be divided in two parts, 16235 and 601561, that added together give a square (617796 = 786²).

The spelling of 16235601561 in words is "sixteen billion, two hundred thirty-five million, six hundred one thousand, five hundred sixty-one".