21870575 has 6 divisors (see below), whose sum is σ = 27119544. Its totient is φ = 17496440.

The previous prime is 21870559. The next prime is 21870587. The reversal of 21870575 is 57507812.

It is not a de Polignac number, because 21870575 - 2⁴ = 21870559 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 437387 + ... + 437436.

It is an arithmetic number, because the mean of its divisors is an integer number (4519924).

Almost surely, 2^21870575 is an apocalyptic number.

21870575 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21870575 is a deficient number, since it is larger than the sum of its proper divisors (5248969).

21870575 is an equidigital number, since it uses as much as digits as its factorization.

21870575 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 874833 (or 874828 counting only the distinct ones).

The product of its (nonzero) digits is 19600, while the sum is 35.

The square root of 21870575 is about 4676.5986571439. The cubic root of 21870575 is about 279.6533763493.

The spelling of 21870575 in words is "twenty-one million, eight hundred seventy thousand, five hundred seventy-five".