21915941 has 12 divisors (see below), whose sum is σ = 24267852. Its totient is φ = 19721856.

The previous prime is 21915931. The next prime is 21915953. The reversal of 21915941 is 14951912.

It can be written as a sum of positive squares in 2 ways, for example, as 19096900 + 2819041 = 4370^2 + 1679^2 .

It is a de Polignac number, because none of the positive numbers 2^k-21915941 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21915898 and 21915907.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21915931) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7775 + ... + 10211.

It is an arithmetic number, because the mean of its divisors is an integer number (2022321).

Almost surely, 2^21915941 is an apocalyptic number.

It is an amenable number.

21915941 is a deficient number, since it is larger than the sum of its proper divisors (2351911).

21915941 is a wasteful number, since it uses less digits than its factorization.

21915941 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2500 (or 2477 counting only the distinct ones).

The product of its digits is 3240, while the sum is 32.

The square root of 21915941 is about 4681.4464645022. The cubic root of 21915941 is about 279.8466039035.

The spelling of 21915941 in words is "twenty-one million, nine hundred fifteen thousand, nine hundred forty-one".