1561338380 has 24 divisors (see below), whose sum is σ = 3747212448. Its totient is φ = 535315968.

The previous prime is 1561338377. The next prime is 1561338391. The reversal of 1561338380 is 838331651.

It is a super-2 number, since 2×1561338380² = 4875555073722048800, which contains 22 as substring.

It is a Smith number, since the sum of its digits (38) coincides with the sum of the digits of its prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5576069 + ... + 5576348.

It is an arithmetic number, because the mean of its divisors is an integer number (156133852).

Almost surely, 2^1561338380 is an apocalyptic number.

1561338380 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1561338380 is an abundant number, since it is smaller than the sum of its proper divisors (2185874068).

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

1561338380 is a wasteful number, since it uses less digits than its factorization.

1561338380 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11152433 (or 11152431 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 38.

The square root of 1561338380 is about 39513.7745602720. The cubic root of 1561338380 is about 1160.1095764502.

The spelling of 1561338380 in words is "one billion, five hundred sixty-one million, three hundred thirty-eight thousand, three hundred eighty".