21041649 has 12 divisors (see below), whose sum is σ = 30437316. Its totient is φ = 14007552.

The previous prime is 21041639. The next prime is 21041659. The reversal of 21041649 is 94614012.

21041649 is a `hidden beast` number, since 2 + 10 + 4 + 1 + 649 = 666.

It is an interprime number because it is at equal distance from previous prime (21041639) and next prime (21041659).

It can be written as a sum of positive squares in 2 ways, for example, as 9345249 + 11696400 = 3057^2 + 3420^2 .

It is not a de Polignac number, because 21041649 - 2⁷ = 21041521 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21041609) 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, 7597 + ... + 9989.

It is an arithmetic number, because the mean of its divisors is an integer number (2536443).

Almost surely, 2^21041649 is an apocalyptic number.

It is an amenable number.

21041649 is a deficient number, since it is larger than the sum of its proper divisors (9395667).

21041649 is a wasteful number, since it uses less digits than its factorization.

21041649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3376 (or 3373 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 21041649 is about 4587.1177224920. The cubic root of 21041649 is about 276.0746883564.

The spelling of 21041649 in words is "twenty-one million, forty-one thousand, six hundred forty-nine".