371391517561 has 9 divisors (see below), whose sum is σ = 374897092143. Its totient is φ = 367918438680.

The previous prime is 371391517531. The next prime is 371391517573. The reversal of 371391517561 is 165715193173.

The square root of 371391517561 is 609419.

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., 258858105961 + 112533411600 = 508781^2 + 335460^2 .

It is not a de Polignac number, because 371391517561 - 2¹⁹ = 371390993273 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (371391517531) 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, 66423876 + ... + 66429466.

Almost surely, 2^371391517561 is an apocalyptic number.

371391517561 is the 609419-th square number.

371391517561 is the 304710-th centered octagonal number.

It is an amenable number.

371391517561 is a deficient number, since it is larger than the sum of its proper divisors (3505574582).

371391517561 is an frugal number, since it uses more digits than its factorization.

371391517561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11400 (or 5700 counting only the distinct ones).

The product of its digits is 595350, while the sum is 49.

Multiplying 371391517561 by its sum of digits (49), we get a square (18198184360489 = 4265933²).

The spelling of 371391517561 in words is "three hundred seventy-one billion, three hundred ninety-one million, five hundred seventeen thousand, five hundred sixty-one".