21540386 has 8 divisors (see below), whose sum is σ = 36926400. Its totient is φ = 9231588.

The previous prime is 21540383. The next prime is 21540437. The reversal of 21540386 is 68304512.

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

It is not an unprimeable number, because it can be changed into a prime (21540383) 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, 769286 + ... + 769313.

It is an arithmetic number, because the mean of its divisors is an integer number (4615800).

Almost surely, 2^21540386 is an apocalyptic number.

21540386 is a deficient number, since it is larger than the sum of its proper divisors (15386014).

21540386 is a wasteful number, since it uses less digits than its factorization.

21540386 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1538608.

The product of its (nonzero) digits is 5760, while the sum is 29.

The square root of 21540386 is about 4641.1621389475. The cubic root of 21540386 is about 278.2388868440.

Adding to 21540386 its reverse (68304512), we get a palindrome (89844898).

The spelling of 21540386 in words is "twenty-one million, five hundred forty thousand, three hundred eighty-six".