21521650 has 12 divisors (see below), whose sum is σ = 40030362. Its totient is φ = 8608640.

The previous prime is 21521627. The next prime is 21521653. The reversal of 21521650 is 5612512.

It can be written as a sum of positive squares in 3 ways, for example, as 20169081 + 1352569 = 4491^2 + 1163^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21521653) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 215167 + ... + 215266.

Almost surely, 2^21521650 is an apocalyptic number.

21521650 is a deficient number, since it is larger than the sum of its proper divisors (18508712).

21521650 is a wasteful number, since it uses less digits than its factorization.

21521650 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 430445 (or 430440 counting only the distinct ones).

The product of its (nonzero) digits is 600, while the sum is 22.

The square root of 21521650 is about 4639.1432398666. The cubic root of 21521650 is about 278.1581919735.

The spelling of 21521650 in words is "twenty-one million, five hundred twenty-one thousand, six hundred fifty".