1561964599 has 4 divisors (see below), whose sum is σ = 1682115736. Its totient is φ = 1441813464.

The previous prime is 1561964567. The next prime is 1561964603. The reversal of 1561964599 is 9954691651.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9954691651 = 43 ⋅231504457.

It is not a de Polignac number, because 1561964599 - 2⁵ = 1561964567 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1561964549) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 60075549 + ... + 60075574.

It is an arithmetic number, because the mean of its divisors is an integer number (420528934).

Almost surely, 2^1561964599 is an apocalyptic number.

1561964599 is a deficient number, since it is larger than the sum of its proper divisors (120151137).

1561964599 is a wasteful number, since it uses less digits than its factorization.

1561964599 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 120151136.

The product of its digits is 2624400, while the sum is 55.

The square root of 1561964599 is about 39521.6978253718. The cubic root of 1561964599 is about 1160.2646539923.

The spelling of 1561964599 in words is "one billion, five hundred sixty-one million, nine hundred sixty-four thousand, five hundred ninety-nine".