21227040 has 72 divisors (see below), whose sum is σ = 72442188. Its totient is φ = 5660160.

The previous prime is 21227023. The next prime is 21227081. The reversal of 21227040 is 4072212.

It can be written as a sum of positive squares in 2 ways, for example, as 20034576 + 1192464 = 4476^2 + 1092^2 .

It is a tau number, because it is divible by the number of its divisors (72).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5931 + ... + 8810.

Almost surely, 2^21227040 is an apocalyptic number.

21227040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21227040 is an abundant number, since it is smaller than the sum of its proper divisors (51215148).

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

21227040 is a wasteful number, since it uses less digits than its factorization.

21227040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14762 (or 14751 counting only the distinct ones).

The product of its (nonzero) digits is 224, while the sum is 18.

The square root of 21227040 is about 4607.2811939364. The cubic root of 21227040 is about 276.8831195909.

Adding to 21227040 its reverse (4072212), we get a palindrome (25299252).

The spelling of 21227040 in words is "twenty-one million, two hundred twenty-seven thousand, forty".