1978172 has 48 divisors (see below), whose sum is σ = 4257792. Its totient is φ = 786240.

The previous prime is 1978159. The next prime is 1978181. The reversal of 1978172 is 2718791.

1978172 = T₁₁₃ + T₁₁₄ + ... + T₂₃₆.

It is a super-3 number, since 3×1978172³ = 23222737107901633344, which contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 37298 + ... + 37350.

It is an arithmetic number, because the mean of its divisors is an integer number (88704).

2^1978172 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1978172, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2128896).

1978172 is an abundant number, since it is smaller than the sum of its proper divisors (2279620).

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

1978172 is a wasteful number, since it uses less digits than its factorization.

1978172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 138 (or 136 counting only the distinct ones).

The product of its digits is 7056, while the sum is 35.

The square root of 1978172 is about 1406.4750264402. The cubic root of 1978172 is about 125.5320680156.

The spelling of 1978172 in words is "one million, nine hundred seventy-eight thousand, one hundred seventy-two".