1561451444 has 72 divisors (see below), whose sum is σ = 3279473568. Its totient is φ = 648298560.

The previous prime is 1561451417. The next prime is 1561451447. The reversal of 1561451444 is 4441541651.

It is a super-2 number, since 2×1561451444² = 4876261223939370272, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1561451447) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 861299 + ... + 863109.

It is an arithmetic number, because the mean of its divisors is an integer number (45548244).

Almost surely, 2^1561451444 is an apocalyptic number.

1561451444 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1561451444, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1639736784).

1561451444 is an abundant number, since it is smaller than the sum of its proper divisors (1718022124).

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

1561451444 is a wasteful number, since it uses less digits than its factorization.

1561451444 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1965 (or 1956 counting only the distinct ones).

The product of its digits is 38400, while the sum is 35.

The square root of 1561451444 is about 39515.2052253307. The cubic root of 1561451444 is about 1160.1375788070.

The spelling of 1561451444 in words is "one billion, five hundred sixty-one million, four hundred fifty-one thousand, four hundred forty-four".