21029375 has 10 divisors (see below), whose sum is σ = 26279088. Its totient is φ = 16823000.

The previous prime is 21029369. The next prime is 21029387. The reversal of 21029375 is 57392012.

It is not a de Polignac number, because 21029375 - 2¹⁴ = 21012991 is a prime.

It is a super-2 number, since 2×21029375² = 884469225781250, which contains 22 as substring.

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 9 ways as a sum of consecutive naturals, for example, 16199 + ... + 17448.

Almost surely, 2^21029375 is an apocalyptic number.

21029375 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21029375 is a deficient number, since it is larger than the sum of its proper divisors (5249713).

21029375 is an frugal number, since it uses more digits than its factorization.

21029375 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33667 (or 33652 counting only the distinct ones).

The product of its (nonzero) digits is 3780, while the sum is 29.

The square root of 21029375 is about 4585.7796501795. The cubic root of 21029375 is about 276.0209980174.

The spelling of 21029375 in words is "twenty-one million, twenty-nine thousand, three hundred seventy-five".