1561436940 has 72 divisors (see below), whose sum is σ = 5085832752. Its totient is φ = 356899200.

The previous prime is 1561436909. The next prime is 1561436957. The reversal of 1561436940 is 496341651.

It is a super-3 number, since 3×1561436940³ (a number of 29 digits) contains 333 as substring.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 262611 + ... + 268490.

It is an arithmetic number, because the mean of its divisors is an integer number (70636566).

Almost surely, 2^1561436940 is an apocalyptic number.

1561436940 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1561436940 is an abundant number, since it is smaller than the sum of its proper divisors (3524395812).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1561436940 is a wasteful number, since it uses less digits than its factorization.

1561436940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 531127 (or 531118 counting only the distinct ones).

The product of its (nonzero) digits is 77760, while the sum is 39.

The square root of 1561436940 is about 39515.0217006141. The cubic root of 1561436940 is about 1160.1339867031.

The spelling of 1561436940 in words is "one billion, five hundred sixty-one million, four hundred thirty-six thousand, nine hundred forty".