21142455 has 16 divisors (see below), whose sum is σ = 34615680. Its totient is φ = 11013408.

The previous prime is 21142447. The next prime is 21142463. The reversal of 21142455 is 55424112.

It is an interprime number because it is at equal distance from previous prime (21142447) and next prime (21142463).

It is not a de Polignac number, because 21142455 - 2³ = 21142447 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15745 + ... + 17034.

It is an arithmetic number, because the mean of its divisors is an integer number (2163480).

Almost surely, 2^21142455 is an apocalyptic number.

21142455 is a deficient number, since it is larger than the sum of its proper divisors (13473225).

21142455 is a wasteful number, since it uses less digits than its factorization.

21142455 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32830.

The product of its digits is 1600, while the sum is 24.

The square root of 21142455 is about 4598.0925393037. The cubic root of 21142455 is about 276.5148576045.

Adding to 21142455 its reverse (55424112), we get a palindrome (76566567).

The spelling of 21142455 in words is "twenty-one million, one hundred forty-two thousand, four hundred fifty-five".