1978724851 has 16 divisors (see below), whose sum is σ = 2057096800. Its totient is φ = 1902071808.

The previous prime is 1978724849. The next prime is 1978724861. The reversal of 1978724851 is 1584278791.

It is a cyclic number.

It is not a de Polignac number, because 1978724851 - 2¹ = 1978724849 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1978724801) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 734515 + ... + 737203.

It is an arithmetic number, because the mean of its divisors is an integer number (128568550).

Almost surely, 2^1978724851 is an apocalyptic number.

1978724851 is a deficient number, since it is larger than the sum of its proper divisors (78371949).

1978724851 is a wasteful number, since it uses less digits than its factorization.

1978724851 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2998.

The product of its digits is 1128960, while the sum is 52.

The square root of 1978724851 is about 44482.8601935622. The cubic root of 1978724851 is about 1255.4376131382.

The spelling of 1978724851 in words is "one billion, nine hundred seventy-eight million, seven hundred twenty-four thousand, eight hundred fifty-one".