21768142 has 24 divisors (see below), whose sum is σ = 36130248. Its totient is φ = 9828720.

The previous prime is 21768133. The next prime is 21768179. The reversal of 21768142 is 24186712.

It is a super-2 number, since 2×21768142² = 947704012264328, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

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, 70753 + ... + 71059.

It is an arithmetic number, because the mean of its divisors is an integer number (1505427).

Almost surely, 2^21768142 is an apocalyptic number.

21768142 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21768142 is a deficient number, since it is larger than the sum of its proper divisors (14362106).

21768142 is a wasteful number, since it uses less digits than its factorization.

21768142 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 624 (or 613 counting only the distinct ones).

The product of its digits is 5376, while the sum is 31.

The square root of 21768142 is about 4665.6341476802. The cubic root of 21768142 is about 279.2160982144.

The spelling of 21768142 in words is "twenty-one million, seven hundred sixty-eight thousand, one hundred forty-two".