21551450 has 12 divisors (see below), whose sum is σ = 40085790. Its totient is φ = 8620560.

The previous prime is 21551449. The next prime is 21551459. The reversal of 21551450 is 5415512.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 14417209 + 7134241 = 3797^2 + 2671^2 .

It is not an unprimeable number, because it can be changed into a prime (21551459) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 215465 + ... + 215564.

Almost surely, 2^21551450 is an apocalyptic number.

21551450 is a deficient number, since it is larger than the sum of its proper divisors (18534340).

21551450 is a wasteful number, since it uses less digits than its factorization.

21551450 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 431041 (or 431036 counting only the distinct ones).

The product of its (nonzero) digits is 1000, while the sum is 23.

The square root of 21551450 is about 4642.3539287736. The cubic root of 21551450 is about 278.2865168807.

Adding to 21551450 its reverse (5415512), we get a palindrome (26966962).

The spelling of 21551450 in words is "twenty-one million, five hundred fifty-one thousand, four hundred fifty".