21447042 has 16 divisors (see below), whose sum is σ = 43377120. Its totient is φ = 7068512.

The previous prime is 21447011. The next prime is 21447043. The reversal of 21447042 is 24074412.

It is a super-2 number, since 2×21447042² = 919951221099528, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21447043) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19548 + ... + 20615.

It is an arithmetic number, because the mean of its divisors is an integer number (2711070).

Almost surely, 2^21447042 is an apocalyptic number.

21447042 is an abundant number, since it is smaller than the sum of its proper divisors (21930078).

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

21447042 is a wasteful number, since it uses less digits than its factorization.

21447042 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40257.

The product of its (nonzero) digits is 1792, while the sum is 24.

The square root of 21447042 is about 4631.0951188677. The cubic root of 21447042 is about 277.8363942551.

The spelling of 21447042 in words is "twenty-one million, four hundred forty-seven thousand, forty-two".