1565978923 has 2 divisors, whose sum is σ = 1565978924. Its totient is φ = 1565978922.

The previous prime is 1565978899. The next prime is 1565979061. The reversal of 1565978923 is 3298795651.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1565978923 is a prime.

It is not a weakly prime, because it can be changed into another prime (1565973923) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 782989461 + 782989462.

It is an arithmetic number, because the mean of its divisors is an integer number (782989462).

Almost surely, 2^1565978923 is an apocalyptic number.

1565978923 is a deficient number, since it is larger than the sum of its proper divisors (1).

1565978923 is an equidigital number, since it uses as much as digits as its factorization.

1565978923 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4082400, while the sum is 55.

The square root of 1565978923 is about 39572.4515667149. The cubic root of 1565978923 is about 1161.2577823012.

The spelling of 1565978923 in words is "one billion, five hundred sixty-five million, nine hundred seventy-eight thousand, nine hundred twenty-three".