21212049 has 16 divisors (see below), whose sum is σ = 29699712. Its totient is φ = 13440768.

The previous prime is 21212033. The next prime is 21212071. The reversal of 21212049 is 94021212.

It is not a de Polignac number, because 21212049 - 2⁴ = 21212033 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21212089) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11049 + ... + 12825.

It is an arithmetic number, because the mean of its divisors is an integer number (1856232).

Almost surely, 2^21212049 is an apocalyptic number.

It is an amenable number.

21212049 is a deficient number, since it is larger than the sum of its proper divisors (8487663).

21212049 is a wasteful number, since it uses less digits than its factorization.

21212049 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1976.

The product of its (nonzero) digits is 288, while the sum is 21.

The square root of 21212049 is about 4605.6540252173. The cubic root of 21212049 is about 276.8179239357.

The spelling of 21212049 in words is "twenty-one million, two hundred twelve thousand, forty-nine".