1561672106 has 4 divisors (see below), whose sum is σ = 2342508162. Its totient is φ = 780836052.

The previous prime is 1561672081. The next prime is 1561672109. The reversal of 1561672106 is 6012761651.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 6012761651 = 13 ⋅462520127.

It can be written as a sum of positive squares in only one way, i.e., 869719081 + 691953025 = 29491^2 + 26305^2 .

It is not an unprimeable number, because it can be changed into a prime (1561672109) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 390418025 + ... + 390418028.

Almost surely, 2^1561672106 is an apocalyptic number.

1561672106 is a deficient number, since it is larger than the sum of its proper divisors (780836056).

1561672106 is an equidigital number, since it uses as much as digits as its factorization.

1561672106 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 780836055.

The product of its (nonzero) digits is 15120, while the sum is 35.

The square root of 1561672106 is about 39517.9972417632. The cubic root of 1561672106 is about 1160.1922258730.

The spelling of 1561672106 in words is "one billion, five hundred sixty-one million, six hundred seventy-two thousand, one hundred six".