1561229816 has 32 divisors (see below), whose sum is σ = 3175109280. Its totient is φ = 716774400.

The previous prime is 1561229807. The next prime is 1561229849. The reversal of 1561229816 is 6189221651.

It is a Harshad number since it is a multiple of its sum of digits (41).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 134420 + ... + 145571.

It is an arithmetic number, because the mean of its divisors is an integer number (99222165).

Almost surely, 2^1561229816 is an apocalyptic number.

It is an amenable number.

1561229816 is an abundant number, since it is smaller than the sum of its proper divisors (1613879464).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1561229816 is a wasteful number, since it uses less digits than its factorization.

1561229816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 280055 (or 280051 counting only the distinct ones).

The product of its digits is 51840, while the sum is 41.

The square root of 1561229816 is about 39512.4007876008. The cubic root of 1561229816 is about 1160.0826873281.

The spelling of 1561229816 in words is "one billion, five hundred sixty-one million, two hundred twenty-nine thousand, eight hundred sixteen".