21000001194 has 56 divisors (see below), whose sum is σ = 47261236932. Its totient is φ = 6995134080.

The previous prime is 21000001193. The next prime is 21000001201. The reversal of 21000001194 is 49110000012.

It can be written as a sum of positive squares in 2 ways, for example, as 19826048025 + 1173953169 = 140805^2 + 34263^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21000001193) by changing a digit.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 2534242 + ... + 2542514.

Almost surely, 2^21000001194 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21000001194, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23630618466).

21000001194 is an abundant number, since it is smaller than the sum of its proper divisors (26261235738).

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

21000001194 is an equidigital number, since it uses as much as digits as its factorization.

21000001194 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10034 (or 10019 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 18.

The spelling of 21000001194 in words is "twenty-one billion, one thousand, one hundred ninety-four".