120699961561 has 9 divisors (see below), whose sum is σ = 121919328639. Its totient is φ = 119492680536.

The previous prime is 120699961553. The next prime is 120699961601. The reversal of 120699961561 is 165169996021.

It is a happy number.

The square root of 120699961561 is 347419.

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

It can be written as a sum of positive squares in only one way, i.e., 119415169225 + 1284792336 = 345565^2 + 35844^2 .

It is not a de Polignac number, because 120699961561 - 2³ = 120699961553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (120699961511) 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, 35782471 + ... + 35785843.

It is an arithmetic number, because the mean of its divisors is an integer number (13546592071).

Almost surely, 2^120699961561 is an apocalyptic number.

120699961561 is the 347419-th square number.

120699961561 is the 173710-th centered octagonal number.

It is an amenable number.

120699961561 is a deficient number, since it is larger than the sum of its proper divisors (1219367078).

120699961561 is an frugal number, since it uses more digits than its factorization.

120699961561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6952 (or 3476 counting only the distinct ones).

The product of its (nonzero) digits is 1574640, while the sum is 55.

The spelling of 120699961561 in words is "one hundred twenty billion, six hundred ninety-nine million, nine hundred sixty-one thousand, five hundred sixty-one".