1561477345 has 4 divisors (see below), whose sum is σ = 1873772820. Its totient is φ = 1249181872.

The previous prime is 1561477331. The next prime is 1561477349. The reversal of 1561477345 is 5437741651.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1118501136 + 442976209 = 33444^2 + 21047^2 .

It is a cyclic number.

It is not a de Polignac number, because 1561477345 - 2¹⁹ = 1560953057 is a prime.

It is a super-2 number, since 2×1561477345² = 4876422997896498050, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1561477349) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 156147730 + ... + 156147739.

It is an arithmetic number, because the mean of its divisors is an integer number (468443205).

Almost surely, 2^1561477345 is an apocalyptic number.

It is an amenable number.

1561477345 is a deficient number, since it is larger than the sum of its proper divisors (312295475).

1561477345 is an equidigital number, since it uses as much as digits as its factorization.

1561477345 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 312295474.

The product of its digits is 352800, while the sum is 43.

The square root of 1561477345 is about 39515.5329585721. The cubic root of 1561477345 is about 1160.1439934706.

The spelling of 1561477345 in words is "one billion, five hundred sixty-one million, four hundred seventy-seven thousand, three hundred forty-five".