1379640525561 has 81 divisors (see below), whose sum is σ = 2200822945581. Its totient is φ = 864641962368.

The previous prime is 1379640525553. The next prime is 1379640525569. The reversal of 1379640525561 is 1655250469731.

The square root of 1379640525561 is 1174581.

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

1379640525561 is a `hidden beast` number, since 1 + 3 + 7 + 9 + 64 + 0 + 525 + 56 + 1 = 666.

It is an interprime number because it is at equal distance from previous prime (1379640525553) and next prime (1379640525569).

It can be written as a sum of positive squares in 4 ways, for example, as 82638425961 + 1297002099600 = 287469^2 + 1138860^2 .

It is a tau number, because it is divible by the number of its divisors (81).

It is not a de Polignac number, because 1379640525561 - 2³ = 1379640525553 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1379640525498 and 1379640525507.

It is not an unprimeable number, because it can be changed into a prime (1379640525569) by changing a digit.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 1617397611 + ... + 1617398463.

Almost surely, 2^{1379640525561} is an apocalyptic number.

1379640525561 is the 1174581-st square number.

1379640525561 is the 587291-st centered octagonal number.

It is an amenable number.

1379640525561 is a deficient number, since it is larger than the sum of its proper divisors (821182420020).

1379640525561 is an frugal number, since it uses more digits than its factorization.

1379640525561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1764 (or 873 counting only the distinct ones).

The product of its (nonzero) digits is 6804000, while the sum is 54.

The spelling of 1379640525561 in words is "one trillion, three hundred seventy-nine billion, six hundred forty million, five hundred twenty-five thousand, five hundred sixty-one".