1561978362 has 64 divisors (see below), whose sum is σ = 3627417600. Its totient is φ = 439171200.

The previous prime is 1561978361. The next prime is 1561978381. The reversal of 1561978362 is 2638791651.

It is not an unprimeable number, because it can be changed into a prime (1561978361) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1356487 + ... + 1357637.

It is an arithmetic number, because the mean of its divisors is an integer number (56678400).

Almost surely, 2^1561978362 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1561978362, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1813708800).

1561978362 is an abundant number, since it is smaller than the sum of its proper divisors (2065439238).

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

1561978362 is a wasteful number, since it uses less digits than its factorization.

1561978362 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1651.

The product of its digits is 544320, while the sum is 48.

The square root of 1561978362 is about 39521.8719445322. The cubic root of 1561978362 is about 1160.2680618108.

The spelling of 1561978362 in words is "one billion, five hundred sixty-one million, nine hundred seventy-eight thousand, three hundred sixty-two".