1978138 has 8 divisors (see below), whose sum is σ = 3096288. Its totient is φ = 946044.

The previous prime is 1978117. The next prime is 1978153. The reversal of 1978138 is 8318791.

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

It is a junction number, because it is equal to n+sod(n) for n = 1978097 and 1978106.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21456 + ... + 21547.

It is an arithmetic number, because the mean of its divisors is an integer number (387036).

2^1978138 is an apocalyptic number.

1978138 is a deficient number, since it is larger than the sum of its proper divisors (1118150).

1978138 is a wasteful number, since it uses less digits than its factorization.

1978138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43028.

The product of its digits is 12096, while the sum is 37.

The square root of 1978138 is about 1406.4629394335. The cubic root of 1978138 is about 125.5313488138.

It can be divided in two parts, 1978 and 138, that added together give a square (2116 = 46²).

The spelling of 1978138 in words is "one million, nine hundred seventy-eight thousand, one hundred thirty-eight".