21431934 has 24 divisors (see below), whose sum is σ = 49168080. Its totient is φ = 6723648.

The previous prime is 21431933. The next prime is 21431939. The reversal of 21431934 is 43913412.

It is a junction number, because it is equal to n+sod(n) for n = 21431898 and 21431907.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21431933) 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 11 ways as a sum of consecutive naturals, for example, 34714 + ... + 35325.

It is an arithmetic number, because the mean of its divisors is an integer number (2048670).

Almost surely, 2^21431934 is an apocalyptic number.

21431934 is an abundant number, since it is smaller than the sum of its proper divisors (27736146).

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

21431934 is a wasteful number, since it uses less digits than its factorization.

21431934 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70064 (or 70061 counting only the distinct ones).

The product of its digits is 2592, while the sum is 27.

The square root of 21431934 is about 4629.4636838407. The cubic root of 21431934 is about 277.7711399066.

The spelling of 21431934 in words is "twenty-one million, four hundred thirty-one thousand, nine hundred thirty-four".