21445430 has 16 divisors (see below), whose sum is σ = 40280544. Its totient is φ = 8205120.

The previous prime is 21445409. The next prime is 21445441. The reversal of 21445430 is 3454412.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is a junction number, because it is equal to n+sod(n) for n = 21445396 and 21445405.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 46391 + ... + 46850.

It is an arithmetic number, because the mean of its divisors is an integer number (2517534).

Almost surely, 2^21445430 is an apocalyptic number.

21445430 is a deficient number, since it is larger than the sum of its proper divisors (18835114).

21445430 is a wasteful number, since it uses less digits than its factorization.

21445430 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 93271.

The product of its (nonzero) digits is 1920, while the sum is 23.

The square root of 21445430 is about 4630.9210746891. The cubic root of 21445430 is about 277.8294331788.

Adding to 21445430 its reverse (3454412), we get a palindrome (24899842).

The spelling of 21445430 in words is "twenty-one million, four hundred forty-five thousand, four hundred thirty".