201549978 has 64 divisors (see below), whose sum is σ = 520323840. Its totient is φ = 56635200.

The previous prime is 201549949. The next prime is 201549983. The reversal of 201549978 is 879945102.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 18688 + ... + 27428.

It is an arithmetic number, because the mean of its divisors is an integer number (8130060).

Almost surely, 2^201549978 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 201549978, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (260161920).

201549978 is an abundant number, since it is smaller than the sum of its proper divisors (318773862).

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

201549978 is a wasteful number, since it uses less digits than its factorization.

201549978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8820 (or 8814 counting only the distinct ones).

The product of its (nonzero) digits is 181440, while the sum is 45.

The square root of 201549978 is about 14196.8298574013. The cubic root of 201549978 is about 586.3103827737.

The spelling of 201549978 in words is "two hundred one million, five hundred forty-nine thousand, nine hundred seventy-eight".