21974541 has 4 divisors (see below), whose sum is σ = 29299392. Its totient is φ = 14649692.

The previous prime is 21974503. The next prime is 21974543. The reversal of 21974541 is 14547912.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21974541 - 2⁷ = 21974413 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21974543) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3662421 + ... + 3662426.

It is an arithmetic number, because the mean of its divisors is an integer number (7324848).

Almost surely, 2^21974541 is an apocalyptic number.

It is an amenable number.

21974541 is a deficient number, since it is larger than the sum of its proper divisors (7324851).

21974541 is an equidigital number, since it uses as much as digits as its factorization.

21974541 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7324850.

The product of its digits is 10080, while the sum is 33.

The square root of 21974541 is about 4687.7010356890. The cubic root of 21974541 is about 280.0958048007.

The spelling of 21974541 in words is "twenty-one million, nine hundred seventy-four thousand, five hundred forty-one".