21941091 has 8 divisors (see below), whose sum is σ = 32505360. Its totient is φ = 14627376.

The previous prime is 21941053. The next prime is 21941113. The reversal of 21941091 is 19014912.

It is not a de Polignac number, because 21941091 - 2¹⁰ = 21940067 is a prime.

It is a super-2 number, since 2×21941091² = 962822948540562, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 812633 = 21941091 / (2 + 1 + 9 + 4 + 1 + 0 + 9 + 1).

It is not an unprimeable number, because it can be changed into a prime (21941021) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 406290 + ... + 406343.

It is an arithmetic number, because the mean of its divisors is an integer number (4063170).

Almost surely, 2^21941091 is an apocalyptic number.

21941091 is a deficient number, since it is larger than the sum of its proper divisors (10564269).

21941091 is an equidigital number, since it uses as much as digits as its factorization.

21941091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 812642 (or 812636 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 27.

The square root of 21941091 is about 4684.1318299126. The cubic root of 21941091 is about 279.9536105120.

The spelling of 21941091 in words is "twenty-one million, nine hundred forty-one thousand, ninety-one".