21145755 has 8 divisors (see below), whose sum is σ = 33833232. Its totient is φ = 11277728.

The previous prime is 21145753. The next prime is 21145757. The reversal of 21145755 is 55754112.

It is an interprime number because it is at equal distance from previous prime (21145753) and next prime (21145757).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21145755 - 2¹ = 21145753 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21145753) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 704844 + ... + 704873.

It is an arithmetic number, because the mean of its divisors is an integer number (4229154).

Almost surely, 2^21145755 is an apocalyptic number.

21145755 is a deficient number, since it is larger than the sum of its proper divisors (12687477).

21145755 is a wasteful number, since it uses less digits than its factorization.

21145755 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1409725.

The product of its digits is 7000, while the sum is 30.

The square root of 21145755 is about 4598.4513697548. The cubic root of 21145755 is about 276.5292433757.

Adding to 21145755 its reverse (55754112), we get a palindrome (76899867).

The spelling of 21145755 in words is "twenty-one million, one hundred forty-five thousand, seven hundred fifty-five".