21029740 has 24 divisors (see below), whose sum is σ = 44296560. Its totient is φ = 8386368.

The previous prime is 21029719. The next prime is 21029741. The reversal of 21029740 is 4792012.

It is not an unprimeable number, because it can be changed into a prime (21029741) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6051 + ... + 8869.

It is an arithmetic number, because the mean of its divisors is an integer number (1845690).

Almost surely, 2^21029740 is an apocalyptic number.

21029740 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21029740 is an abundant number, since it is smaller than the sum of its proper divisors (23266820).

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

21029740 is a wasteful number, since it uses less digits than its factorization.

21029740 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3201 (or 3199 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 25.

The square root of 21029740 is about 4585.8194469473. The cubic root of 21029740 is about 276.0225949436.

The spelling of 21029740 in words is "twenty-one million, twenty-nine thousand, seven hundred forty".