1956671561 has 8 divisors (see below), whose sum is σ = 2114052864. Its totient is φ = 1800271440.

The previous prime is 1956671503. The next prime is 1956671567. The reversal of 1956671561 is 1651766591.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1956671561 - 2¹⁰ = 1956670537 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1956671567) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 241145 + ... + 249126.

It is an arithmetic number, because the mean of its divisors is an integer number (264256608).

Almost surely, 2^1956671561 is an apocalyptic number.

It is an amenable number.

1956671561 is a deficient number, since it is larger than the sum of its proper divisors (157381303).

1956671561 is a wasteful number, since it uses less digits than its factorization.

1956671561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 490591.

The product of its digits is 340200, while the sum is 47.

The square root of 1956671561 is about 44234.2803829790. The cubic root of 1956671561 is about 1250.7561421870.

The spelling of 1956671561 in words is "one billion, nine hundred fifty-six million, six hundred seventy-one thousand, five hundred sixty-one".