21994061 has 4 divisors (see below), whose sum is σ = 22010652. Its totient is φ = 21977472.

The previous prime is 21994057. The next prime is 21994069. The reversal of 21994061 is 16049912.

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 18361225 + 3632836 = 4285^2 + 1906^2 .

It is a cyclic number.

It is not a de Polignac number, because 21994061 - 2² = 21994057 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 (21994069) 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, 6116 + ... + 9021.

It is an arithmetic number, because the mean of its divisors is an integer number (5502663).

Almost surely, 2^21994061 is an apocalyptic number.

It is an amenable number.

21994061 is a deficient number, since it is larger than the sum of its proper divisors (16591).

21994061 is a wasteful number, since it uses less digits than its factorization.

21994061 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16590.

The product of its (nonzero) digits is 3888, while the sum is 32.

The square root of 21994061 is about 4689.7826175634. The cubic root of 21994061 is about 280.1787166878.

The spelling of 21994061 in words is "twenty-one million, nine hundred ninety-four thousand, sixty-one".