1978172801 has 16 divisors (see below), whose sum is σ = 2219857920. Its totient is φ = 1747350480.

The previous prime is 1978172771. The next prime is 1978172831. The reversal of 1978172801 is 1082718791.

It is an interprime number because it is at equal distance from previous prime (1978172771) and next prime (1978172831).

It is a cyclic number.

It is not a de Polignac number, because 1978172801 - 2¹⁰ = 1978171777 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1978172831) 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, 58100 + ... + 85626.

It is an arithmetic number, because the mean of its divisors is an integer number (138741120).

Almost surely, 2^1978172801 is an apocalyptic number.

1978172801 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1978172801 is a deficient number, since it is larger than the sum of its proper divisors (241685119).

1978172801 is a wasteful number, since it uses less digits than its factorization.

1978172801 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27724.

The product of its (nonzero) digits is 56448, while the sum is 44.

The square root of 1978172801 is about 44476.6545616911. The cubic root of 1978172801 is about 1255.3208495910.

The spelling of 1978172801 in words is "one billion, nine hundred seventy-eight million, one hundred seventy-two thousand, eight hundred one".