1561264437 has 4 divisors (see below), whose sum is σ = 2081685920. Its totient is φ = 1040842956.

The previous prime is 1561264423. The next prime is 1561264451. The reversal of 1561264437 is 7344621651.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (1561264423) and next prime (1561264451).

It is not a de Polignac number, because 1561264437 - 2¹⁴ = 1561248053 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1561264395 and 1561264404.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1561264417) 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, 260210737 + ... + 260210742.

It is an arithmetic number, because the mean of its divisors is an integer number (520421480).

Almost surely, 2^1561264437 is an apocalyptic number.

It is an amenable number.

1561264437 is a deficient number, since it is larger than the sum of its proper divisors (520421483).

1561264437 is an equidigital number, since it uses as much as digits as its factorization.

1561264437 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 520421482.

The product of its digits is 120960, while the sum is 39.

The square root of 1561264437 is about 39512.8388881386. The cubic root of 1561264437 is about 1160.0912623897.

The spelling of 1561264437 in words is "one billion, five hundred sixty-one million, two hundred sixty-four thousand, four hundred thirty-seven".