21870455 has 8 divisors (see below), whose sum is σ = 26383104. Its totient is φ = 17404000.

The previous prime is 21870451. The next prime is 21870461. The reversal of 21870455 is 55407812.

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

It is not a de Polignac number, because 21870455 - 2² = 21870451 is a prime.

It is a super-3 number, since 3×21870455³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is a plaindrome in base 8.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21870451) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10496 + ... + 12405.

It is an arithmetic number, because the mean of its divisors is an integer number (3297888).

Almost surely, 2^21870455 is an apocalyptic number.

21870455 is a deficient number, since it is larger than the sum of its proper divisors (4512649).

21870455 is a wasteful number, since it uses less digits than its factorization.

21870455 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23097.

The product of its (nonzero) digits is 11200, while the sum is 32.

The square root of 21870455 is about 4676.5858272890. The cubic root of 21870455 is about 279.6528648788.

The spelling of 21870455 in words is "twenty-one million, eight hundred seventy thousand, four hundred fifty-five".