1561230278 has 4 divisors (see below), whose sum is σ = 2341845420. Its totient is φ = 780615138.

The previous prime is 1561230221. The next prime is 1561230287. The reversal of 1561230278 is 8720321651.

It is a happy number.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 390307568 + ... + 390307571.

It is an arithmetic number, because the mean of its divisors is an integer number (585461355).

Almost surely, 2^1561230278 is an apocalyptic number.

1561230278 is a deficient number, since it is larger than the sum of its proper divisors (780615142).

1561230278 is an equidigital number, since it uses as much as digits as its factorization.

1561230278 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 780615141.

The product of its (nonzero) digits is 20160, while the sum is 35.

The square root of 1561230278 is about 39512.4066338663. The cubic root of 1561230278 is about 1160.0828017588.

The spelling of 1561230278 in words is "one billion, five hundred sixty-one million, two hundred thirty thousand, two hundred seventy-eight".