21237001 has 4 divisors (see below), whose sum is σ = 21811012. Its totient is φ = 20662992.

The previous prime is 21236989. The next prime is 21237011. The reversal of 21237001 is 10073212.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 18481401 + 2755600 = 4299^2 + 1660^2 .

It is a cyclic number.

It is not a de Polignac number, because 21237001 - 2¹¹ = 21234953 is a prime.

It is a super-2 number, since 2×21237001² = 902020422948002, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21237011) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 286950 + ... + 287023.

It is an arithmetic number, because the mean of its divisors is an integer number (5452753).

Almost surely, 2^21237001 is an apocalyptic number.

It is an amenable number.

21237001 is a deficient number, since it is larger than the sum of its proper divisors (574011).

21237001 is an equidigital number, since it uses as much as digits as its factorization.

21237001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 574010.

The product of its (nonzero) digits is 84, while the sum is 16.

The square root of 21237001 is about 4608.3620734487. The cubic root of 21237001 is about 276.9264228723.

The spelling of 21237001 in words is "twenty-one million, two hundred thirty-seven thousand, one".