21055001 has 8 divisors (see below), whose sum is σ = 23260800. Its totient is φ = 18897840.

The previous prime is 21054973. The next prime is 21055003. The reversal of 21055001 is 10055012.

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 21055001 - 2¹⁸ = 20792857 is a prime.

It is a super-2 number, since 2×21055001² = 886626134220002, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21055003) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11246 + ... + 12983.

It is an arithmetic number, because the mean of its divisors is an integer number (2907600).

Almost surely, 2^21055001 is an apocalyptic number.

It is an amenable number.

21055001 is a deficient number, since it is larger than the sum of its proper divisors (2205799).

21055001 is a wasteful number, since it uses less digits than its factorization.

21055001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24319.

The product of its (nonzero) digits is 50, while the sum is 14.

The square root of 21055001 is about 4588.5728718197. The cubic root of 21055001 is about 276.1330705017.

The spelling of 21055001 in words is "twenty-one million, fifty-five thousand, one".