561903994 has 4 divisors (see below), whose sum is σ = 842855994. Its totient is φ = 280951996.

The previous prime is 561903977. The next prime is 561904003. The reversal of 561903994 is 499309165.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 499309165 = 5 ⋅99861833.

It can be written as a sum of positive squares in only one way, i.e., 427042225 + 134861769 = 20665^2 + 11613^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 140475997 + ... + 140476000.

Almost surely, 2^561903994 is an apocalyptic number.

561903994 is a deficient number, since it is larger than the sum of its proper divisors (280952000).

561903994 is a wasteful number, since it uses less digits than its factorization.

561903994 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 280951999.

The product of its (nonzero) digits is 262440, while the sum is 46.

The square root of 561903994 is about 23704.5142114324. The cubic root of 561903994 is about 825.1901583087.

The spelling of 561903994 in words is "five hundred sixty-one million, nine hundred three thousand, nine hundred ninety-four".