1952779861561 has 9 divisors (see below), whose sum is σ = 1982455893999. Its totient is φ = 1923541663824.

The previous prime is 1952779861553. The next prime is 1952779861573. The reversal of 1952779861561 is 1651689772591.

The square root of 1952779861561 is 1397419.

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., 1907727252025 + 45052609536 = 1381205^2 + 212256^2 .

It is not a de Polignac number, because 1952779861561 - 2³ = 1952779861553 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (67).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1952779861541) 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, 93616645 + ... + 93637501.

It is an arithmetic number, because the mean of its divisors is an integer number (220272877111).

Almost surely, 2^{1952779861561} is an apocalyptic number.

1952779861561 is the 1397419-th square number.

1952779861561 is the 698710-th centered octagonal number.

It is an amenable number.

1952779861561 is a deficient number, since it is larger than the sum of its proper divisors (29676032438).

1952779861561 is an frugal number, since it uses more digits than its factorization.

1952779861561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41848 (or 20924 counting only the distinct ones).

The product of its digits is 57153600, while the sum is 67.

The spelling of 1952779861561 in words is "one trillion, nine hundred fifty-two billion, seven hundred seventy-nine million, eight hundred sixty-one thousand, five hundred sixty-one".