21046740 has 144 divisors (see below), whose sum is σ = 70070784. Its totient is φ = 4688640.

The previous prime is 21046733. The next prime is 21046757. The reversal of 21046740 is 4764012.

It is a self number, because there is not a number n which added to its sum of digits gives 21046740.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 94269 + ... + 94491.

Almost surely, 2^21046740 is an apocalyptic number.

21046740 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 21046740, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35035392).

21046740 is an abundant number, since it is smaller than the sum of its proper divisors (49024044).

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

21046740 is a wasteful number, since it uses less digits than its factorization.

21046740 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 270 (or 257 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 24.

The square root of 21046740 is about 4587.6726125564. The cubic root of 21046740 is about 276.0969518666.

The spelling of 21046740 in words is "twenty-one million, forty-six thousand, seven hundred forty".