21024340 has 24 divisors (see below), whose sum is σ = 44265312. Its totient is φ = 8388000.

The previous prime is 21024331. The next prime is 21024361. The reversal of 21024340 is 4342012.

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, 8215 + ... + 10465.

It is an arithmetic number, because the mean of its divisors is an integer number (1844388).

Almost surely, 2^21024340 is an apocalyptic number.

21024340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21024340 is an abundant number, since it is smaller than the sum of its proper divisors (23240972).

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

21024340 is a wasteful number, since it uses less digits than its factorization.

21024340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2727 (or 2725 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 16.

The square root of 21024340 is about 4585.2306376016. The cubic root of 21024340 is about 275.9989672999.

Adding to 21024340 its reverse (4342012), we get a palindrome (25366352).

The spelling of 21024340 in words is "twenty-one million, twenty-four thousand, three hundred forty".