21067641 has 64 divisors (see below), whose sum is σ = 38707200. Its totient is φ = 11052288.

The previous prime is 21067639. The next prime is 21067679. The reversal of 21067641 is 14676012.

21067641 is a `hidden beast` number, since 2 + 10 + 6 + 7 + 641 = 666.

It is not a de Polignac number, because 21067641 - 2¹ = 21067639 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21067621) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 253786 + ... + 253868.

It is an arithmetic number, because the mean of its divisors is an integer number (604800).

Almost surely, 2^21067641 is an apocalyptic number.

21067641 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21067641 is a deficient number, since it is larger than the sum of its proper divisors (17639559).

21067641 is a wasteful number, since it uses less digits than its factorization.

21067641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 195 (or 189 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 27.

The square root of 21067641 is about 4589.9499997277. The cubic root of 21067641 is about 276.1883166606.

The spelling of 21067641 in words is "twenty-one million, sixty-seven thousand, six hundred forty-one".