1561223747 has 8 divisors (see below), whose sum is σ = 1691504496. Its totient is φ = 1435214592.

The previous prime is 1561223717. The next prime is 1561223753. The reversal of 1561223747 is 7473221651.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1561223747 - 2¹⁶ = 1561158211 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1561223747.

It is not an unprimeable number, because it can be changed into a prime (1561223717) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1067138 + ... + 1068599.

It is an arithmetic number, because the mean of its divisors is an integer number (211438062).

Almost surely, 2^1561223747 is an apocalyptic number.

1561223747 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

1561223747 is a deficient number, since it is larger than the sum of its proper divisors (130280749).

1561223747 is a wasteful number, since it uses less digits than its factorization.

1561223747 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2135797.

The product of its digits is 70560, while the sum is 38.

The square root of 1561223747 is about 39512.3239888519. The cubic root of 1561223747 is about 1160.0811841219.

The spelling of 1561223747 in words is "one billion, five hundred sixty-one million, two hundred twenty-three thousand, seven hundred forty-seven".