1561664019 has 8 divisors (see below), whose sum is σ = 2090515392. Its totient is φ = 1036961000.

The previous prime is 1561664011. The next prime is 1561664053. The reversal of 1561664019 is 9104661651.

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 1561664019 - 2³ = 1561664011 is a prime.

It is a super-2 number, since 2×1561664019² = 4877589016478464722, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1561664011) 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, 1036209 + ... + 1037714.

It is an arithmetic number, because the mean of its divisors is an integer number (261314424).

Almost surely, 2^1561664019 is an apocalyptic number.

1561664019 is a deficient number, since it is larger than the sum of its proper divisors (528851373).

1561664019 is a wasteful number, since it uses less digits than its factorization.

1561664019 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2074177.

The product of its (nonzero) digits is 38880, while the sum is 39.

The square root of 1561664019 is about 39517.8949211620. The cubic root of 1561664019 is about 1160.1902232139.

The spelling of 1561664019 in words is "one billion, five hundred sixty-one million, six hundred sixty-four thousand, nineteen".