1978266906 has 96 divisors (see below), whose sum is σ = 5453136000. Its totient is φ = 513817920.

The previous prime is 1978266893. The next prime is 1978266919. The reversal of 1978266906 is 6096628791.

It is an interprime number because it is at equal distance from previous prime (1978266893) and next prime (1978266919).

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is an unprimeable number.

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 47 ways as a sum of consecutive naturals, for example, 53350 + ... + 82478.

It is an arithmetic number, because the mean of its divisors is an integer number (56803500).

Almost surely, 2^1978266906 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1978266906, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2726568000).

1978266906 is an abundant number, since it is smaller than the sum of its proper divisors (3474869094).

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

1978266906 is a wasteful number, since it uses less digits than its factorization.

1978266906 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29169 (or 29152 counting only the distinct ones).

The product of its (nonzero) digits is 1959552, while the sum is 54.

The square root of 1978266906 is about 44477.7124636598. The cubic root of 1978266906 is about 1255.3407551818.

The spelling of 1978266906 in words is "one billion, nine hundred seventy-eight million, two hundred sixty-six thousand, nine hundred six".