21507834 has 16 divisors (see below), whose sum is σ = 43061760. Its totient is φ = 7161600.

The previous prime is 21507833. The next prime is 21507847. The reversal of 21507834 is 43870512.

It is not an unprimeable number, because it can be changed into a prime (21507833) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8487 + ... + 10725.

It is an arithmetic number, because the mean of its divisors is an integer number (2691360).

Almost surely, 2^21507834 is an apocalyptic number.

21507834 is an abundant number, since it is smaller than the sum of its proper divisors (21553926).

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

21507834 is a wasteful number, since it uses less digits than its factorization.

21507834 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3845.

The product of its (nonzero) digits is 6720, while the sum is 30.

The square root of 21507834 is about 4637.6539327552. The cubic root of 21507834 is about 278.0986572534.

The spelling of 21507834 in words is "twenty-one million, five hundred seven thousand, eight hundred thirty-four".