21097149 has 4 divisors (see below), whose sum is σ = 28129536. Its totient is φ = 14064764.

The previous prime is 21097129. The next prime is 21097159. The reversal of 21097149 is 94179012.

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 21097149 - 2⁵ = 21097117 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21097129) 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, 3516189 + ... + 3516194.

It is an arithmetic number, because the mean of its divisors is an integer number (7032384).

Almost surely, 2^21097149 is an apocalyptic number.

It is an amenable number.

21097149 is a deficient number, since it is larger than the sum of its proper divisors (7032387).

21097149 is an equidigital number, since it uses as much as digits as its factorization.

21097149 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7032386.

The product of its (nonzero) digits is 4536, while the sum is 33.

The square root of 21097149 is about 4593.1632890634. The cubic root of 21097149 is about 276.3172025172.

The spelling of 21097149 in words is "twenty-one million, ninety-seven thousand, one hundred forty-nine".