1961781569 has 8 divisors (see below), whose sum is σ = 2160904512. Its totient is φ = 1766121840.

The previous prime is 1961781557. The next prime is 1961781607. The reversal of 1961781569 is 9651871691.

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 1961781569 - 2⁴ = 1961781553 is a prime.

It is a super-2 number, since 2×1961781569² = 7697173848936203522, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1961781569.

It is not an unprimeable number, because it can be changed into a prime (1961781509) 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, 864614 + ... + 866879.

It is an arithmetic number, because the mean of its divisors is an integer number (270113064).

Almost surely, 2^1961781569 is an apocalyptic number.

It is an amenable number.

1961781569 is a deficient number, since it is larger than the sum of its proper divisors (199122943).

1961781569 is a wasteful number, since it uses less digits than its factorization.

1961781569 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1731607.

The product of its digits is 816480, while the sum is 53.

The square root of 1961781569 is about 44292.0034430596. The cubic root of 1961781569 is about 1251.8440130749.

The spelling of 1961781569 in words is "one billion, nine hundred sixty-one million, seven hundred eighty-one thousand, five hundred sixty-nine".