21987301 has 4 divisors (see below), whose sum is σ = 25128352. Its totient is φ = 18846252.

The previous prime is 21987299. The next prime is 21987331. The reversal of 21987301 is 10378912.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21987301 - 2¹ = 21987299 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21987331) 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, 1570515 + ... + 1570528.

It is an arithmetic number, because the mean of its divisors is an integer number (6282088).

Almost surely, 2^21987301 is an apocalyptic number.

It is an amenable number.

21987301 is a deficient number, since it is larger than the sum of its proper divisors (3141051).

21987301 is an equidigital number, since it uses as much as digits as its factorization.

21987301 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3141050.

The product of its (nonzero) digits is 3024, while the sum is 31.

The square root of 21987301 is about 4689.0618464678. The cubic root of 21987301 is about 280.1500089047.

The spelling of 21987301 in words is "twenty-one million, nine hundred eighty-seven thousand, three hundred one".