1561993498 has 16 divisors (see below), whose sum is σ = 2527335720. Its totient is φ = 719744256.

The previous prime is 1561993493. The next prime is 1561993513. The reversal of 1561993498 is 8943991651.

It can be written as a sum of positive squares in 4 ways, for example, as 1178342929 + 383650569 = 34327^2 + 19587^2 .

It is not an unprimeable number, because it can be changed into a prime (1561993493) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 32643 + ... + 64726.

Almost surely, 2^1561993498 is an apocalyptic number.

1561993498 is a deficient number, since it is larger than the sum of its proper divisors (965342222).

1561993498 is a wasteful number, since it uses less digits than its factorization.

1561993498 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 98001.

The product of its digits is 2099520, while the sum is 55.

The square root of 1561993498 is about 39522.0634329737. The cubic root of 1561993498 is about 1160.2718095709.

The spelling of 1561993498 in words is "one billion, five hundred sixty-one million, nine hundred ninety-three thousand, four hundred ninety-eight".