21067040 has 48 divisors (see below), whose sum is σ = 50045688. Its totient is φ = 8380416.

The previous prime is 21067037. The next prime is 21067043. The reversal of 21067040 is 4076012.

It is an interprime number because it is at equal distance from previous prime (21067037) and next prime (21067043).

It can be written as a sum of positive squares in 4 ways, for example, as 16418704 + 4648336 = 4052^2 + 2156^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21067043) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 56294 + ... + 56666.

Almost surely, 2^21067040 is an apocalyptic number.

21067040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21067040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25022844).

21067040 is an abundant number, since it is smaller than the sum of its proper divisors (28978648).

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

21067040 is a wasteful number, since it uses less digits than its factorization.

21067040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 741 (or 733 counting only the distinct ones).

The product of its (nonzero) digits is 336, while the sum is 20.

The square root of 21067040 is about 4589.8845301380. The cubic root of 21067040 is about 276.1856903461.

The spelling of 21067040 in words is "twenty-one million, sixty-seven thousand, forty".