1978881 has 8 divisors (see below), whose sum is σ = 2646240. Its totient is φ = 1315392.

The previous prime is 1978877. The next prime is 1978883. The reversal of 1978881 is 1888791.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1978881 - 2² = 1978877 is a prime.

It is a super-2 number, since 2×1978881² = 7831940024322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1978883) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 585 + ... + 2073.

It is an arithmetic number, because the mean of its divisors is an integer number (330780).

2^1978881 is an apocalyptic number.

It is an amenable number.

1978881 is a deficient number, since it is larger than the sum of its proper divisors (667359).

1978881 is a wasteful number, since it uses less digits than its factorization.

1978881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1935.

The product of its digits is 32256, while the sum is 42.

The square root of 1978881 is about 1406.7270524164. The cubic root of 1978881 is about 125.5470636118.

The spelling of 1978881 in words is "one million, nine hundred seventy-eight thousand, eight hundred eighty-one".