1978761547 has 4 divisors (see below), whose sum is σ = 2261441776. Its totient is φ = 1696081320.

The previous prime is 1978761541. The next prime is 1978761559. The reversal of 1978761547 is 7451678791.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7451678791 = 2099 ⋅3550109.

It is a cyclic number.

It is not a de Polignac number, because 1978761547 - 2¹¹ = 1978759499 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1978761541) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 141340104 + ... + 141340117.

It is an arithmetic number, because the mean of its divisors is an integer number (565360444).

Almost surely, 2^1978761547 is an apocalyptic number.

1978761547 is a deficient number, since it is larger than the sum of its proper divisors (282680229).

1978761547 is an equidigital number, since it uses as much as digits as its factorization.

1978761547 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 282680228.

The product of its digits is 2963520, while the sum is 55.

The square root of 1978761547 is about 44483.2726651266. The cubic root of 1978761547 is about 1255.4453739029.

The spelling of 1978761547 in words is "one billion, nine hundred seventy-eight million, seven hundred sixty-one thousand, five hundred forty-seven".