21488387 has 8 divisors (see below), whose sum is σ = 22084272. Its totient is φ = 20896000.

The previous prime is 21488381. The next prime is 21488399. The reversal of 21488387 is 78388412.

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 21488387 - 2¹² = 21484291 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (41).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21488381) 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, 15788 + ... + 17094.

It is an arithmetic number, because the mean of its divisors is an integer number (2760534).

Almost surely, 2^21488387 is an apocalyptic number.

21488387 is a deficient number, since it is larger than the sum of its proper divisors (595885).

21488387 is a wasteful number, since it uses less digits than its factorization.

21488387 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1749.

The product of its digits is 86016, while the sum is 41.

The square root of 21488387 is about 4635.5568166079. The cubic root of 21488387 is about 278.0148146962.

The spelling of 21488387 in words is "twenty-one million, four hundred eighty-eight thousand, three hundred eighty-seven".