21445402 has 16 divisors (see below), whose sum is σ = 35178624. Its totient is φ = 9724000.

The previous prime is 21445393. The next prime is 21445409. The reversal of 21445402 is 20454412.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is not an unprimeable number, because it can be changed into a prime (21445409) 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, 10527 + ... + 12397.

It is an arithmetic number, because the mean of its divisors is an integer number (2198664).

Almost surely, 2^21445402 is an apocalyptic number.

21445402 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21445402 is a deficient number, since it is larger than the sum of its proper divisors (13733222).

21445402 is a wasteful number, since it uses less digits than its factorization.

21445402 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2405.

The product of its (nonzero) digits is 1280, while the sum is 22.

The square root of 21445402 is about 4630.9180515315. The cubic root of 21445402 is about 277.8293122637.

Adding to 21445402 its reverse (20454412), we get a palindrome (41899814).

The spelling of 21445402 in words is "twenty-one million, four hundred forty-five thousand, four hundred two".