21220434 has 32 divisors (see below), whose sum is σ = 47475840. Its totient is φ = 7025616.

The previous prime is 21220429. The next prime is 21220477. The reversal of 21220434 is 43402212.

21220434 is a `hidden beast` number, since 212 + 20 + 434 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 7227 + ... + 9729.

It is an arithmetic number, because the mean of its divisors is an integer number (1483620).

Almost surely, 2^21220434 is an apocalyptic number.

21220434 is an abundant number, since it is smaller than the sum of its proper divisors (26255406).

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

21220434 is a wasteful number, since it uses less digits than its factorization.

21220434 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2671 (or 2665 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 18.

The square root of 21220434 is about 4606.5642294448. The cubic root of 21220434 is about 276.8543939708.

Adding to 21220434 its reverse (43402212), we get a palindrome (64622646).

The spelling of 21220434 in words is "twenty-one million, two hundred twenty thousand, four hundred thirty-four".