9780749601561 has 45 divisors (see below), whose sum is σ = 15421052392911. Its totient is φ = 6176977776576.

The previous prime is 9780749601559. The next prime is 9780749601577. The reversal of 9780749601561 is 1651069470879.

The square root of 9780749601561 is 3127419.

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

9780749601561 is a `hidden beast` number, since 9 + 7 + 8 + 0 + 7 + 4 + 9 + 60 + 1 + 561 = 666.

It can be written as a sum of positive squares in only one way, i.e., 9644322791961 + 136426809600 = 3105531^2 + 369360^2 .

It is not a de Polignac number, because 9780749601561 - 2¹ = 9780749601559 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (9780749601521) by changing a digit.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 534779505 + ... + 534797793.

Almost surely, 2^{9780749601561} is an apocalyptic number.

9780749601561 is the 3127419-th square number.

9780749601561 is the 1563710-th centered octagonal number.

It is an amenable number.

9780749601561 is a deficient number, since it is larger than the sum of its proper divisors (5640302791350).

9780749601561 is an frugal number, since it uses more digits than its factorization.

9780749601561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36628 (or 18311 counting only the distinct ones).

The product of its (nonzero) digits is 22861440, while the sum is 63.

The spelling of 9780749601561 in words is "nine trillion, seven hundred eighty billion, seven hundred forty-nine million, six hundred one thousand, five hundred sixty-one".