21400489 has 4 divisors (see below), whose sum is σ = 23346000. Its totient is φ = 19454980.

The previous prime is 21400487. The next prime is 21400493. The reversal of 21400489 is 98400412.

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 21400489 - 2¹ = 21400487 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21400487) 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, 972739 + ... + 972760.

It is an arithmetic number, because the mean of its divisors is an integer number (5836500).

Almost surely, 2^21400489 is an apocalyptic number.

It is an amenable number.

21400489 is a deficient number, since it is larger than the sum of its proper divisors (1945511).

21400489 is a wasteful number, since it uses less digits than its factorization.

21400489 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1945510.

The product of its (nonzero) digits is 2304, while the sum is 28.

The square root of 21400489 is about 4626.0662554702. The cubic root of 21400489 is about 277.6352245205.

The spelling of 21400489 in words is "twenty-one million, four hundred thousand, four hundred eighty-nine".