194951821 has 4 divisors (see below), whose sum is σ = 195008572. Its totient is φ = 194895072.

The previous prime is 194951819. The next prime is 194951831. The reversal of 194951821 is 128159491.

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 7645225 + 187306596 = 2765^2 + 13686^2 .

It is a cyclic number.

It is not a de Polignac number, because 194951821 - 2¹ = 194951819 is a prime.

It is a super-2 number, since 2×194951821² = 76012425022432082, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (194951831) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 22866 + ... + 30211.

It is an arithmetic number, because the mean of its divisors is an integer number (48752143).

Almost surely, 2^194951821 is an apocalyptic number.

It is an amenable number.

194951821 is a deficient number, since it is larger than the sum of its proper divisors (56751).

194951821 is an equidigital number, since it uses as much as digits as its factorization.

194951821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56750.

The product of its digits is 25920, while the sum is 40.

The square root of 194951821 is about 13962.5148522750. The cubic root of 194951821 is about 579.8412377591.

It can be divided in two parts, 19495 and 1821, that added together give a square (21316 = 146²).

The spelling of 194951821 in words is "one hundred ninety-four million, nine hundred fifty-one thousand, eight hundred twenty-one".