1978901 has 4 divisors (see below), whose sum is σ = 2011404. Its totient is φ = 1946400.

The previous prime is 1978891. The next prime is 1978909. The reversal of 1978901 is 1098791.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 948676 + 1030225 = 974^2 + 1015^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1978901 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1978909) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16160 + ... + 16281.

It is an arithmetic number, because the mean of its divisors is an integer number (502851).

2^1978901 is an apocalyptic number.

It is an amenable number.

1978901 is a deficient number, since it is larger than the sum of its proper divisors (32503).

1978901 is an equidigital number, since it uses as much as digits as its factorization.

1978901 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32502.

The product of its (nonzero) digits is 4536, while the sum is 35.

The square root of 1978901 is about 1406.7341610980. The cubic root of 1978901 is about 125.5474865668.

The spelling of 1978901 in words is "one million, nine hundred seventy-eight thousand, nine hundred one".