21489387 has 8 divisors (see below), whose sum is σ = 29262336. Its totient is φ = 14021352.

The previous prime is 21489373. The next prime is 21489389. The reversal of 21489387 is 78398412.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21489387 - 2¹² = 21485291 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21489389) 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, 76063 + ... + 76344.

It is an arithmetic number, because the mean of its divisors is an integer number (3657792).

Almost surely, 2^21489387 is an apocalyptic number.

21489387 is a deficient number, since it is larger than the sum of its proper divisors (7772949).

21489387 is a wasteful number, since it uses less digits than its factorization.

21489387 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 152457.

The product of its digits is 96768, while the sum is 42.

The square root of 21489387 is about 4635.6646772604. The cubic root of 21489387 is about 278.0191272660.

The spelling of 21489387 in words is "twenty-one million, four hundred eighty-nine thousand, three hundred eighty-seven".