21481550 has 12 divisors (see below), whose sum is σ = 39955776. Its totient is φ = 8592600.

The previous prime is 21481549. The next prime is 21481561. The reversal of 21481550 is 5518412.

It is a super-2 number, since 2×21481550² = 922913980805000, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 214766 + ... + 214865.

It is an arithmetic number, because the mean of its divisors is an integer number (3329648).

Almost surely, 2^21481550 is an apocalyptic number.

21481550 is a deficient number, since it is larger than the sum of its proper divisors (18474226).

21481550 is a wasteful number, since it uses less digits than its factorization.

21481550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 429643 (or 429638 counting only the distinct ones).

The product of its (nonzero) digits is 1600, while the sum is 26.

The square root of 21481550 is about 4634.8193060787. The cubic root of 21481550 is about 277.9853260719.

Adding to 21481550 its reverse (5518412), we get a palindrome (26999962).

The spelling of 21481550 in words is "twenty-one million, four hundred eighty-one thousand, five hundred fifty".