21433340 has 24 divisors (see below), whose sum is σ = 45217872. Its totient is φ = 8533760.

The previous prime is 21433319. The next prime is 21433351. The reversal of 21433340 is 4333412.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2180 + ... + 6900.

It is an arithmetic number, because the mean of its divisors is an integer number (1884078).

Almost surely, 2^21433340 is an apocalyptic number.

21433340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21433340 is an abundant number, since it is smaller than the sum of its proper divisors (23784532).

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

21433340 is a wasteful number, since it uses less digits than its factorization.

21433340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4957 (or 4955 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 20.

The square root of 21433340 is about 4629.6155347934. The cubic root of 21433340 is about 277.7772139840. Note that the first 3 decimals are identical.

Adding to 21433340 its reverse (4333412), we get a palindrome (25766752).

The spelling of 21433340 in words is "twenty-one million, four hundred thirty-three thousand, three hundred forty".