21649560 has 32 divisors (see below), whose sum is σ = 64949040. Its totient is φ = 5773184.

The previous prime is 21649559. The next prime is 21649577. The reversal of 21649560 is 6594612.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 90087 + ... + 90326.

Almost surely, 2^21649560 is an apocalyptic number.

21649560 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21649560 is an abundant number, since it is smaller than the sum of its proper divisors (43299480).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21649560 is a wasteful number, since it uses less digits than its factorization.

21649560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 180427 (or 180423 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 33.

The square root of 21649560 is about 4652.9087676420. The cubic root of 21649560 is about 278.7081646748.

The spelling of 21649560 in words is "twenty-one million, six hundred forty-nine thousand, five hundred sixty".