21154357 has 8 divisors (see below), whose sum is σ = 24284736. Its totient is φ = 18051072.

The previous prime is 21154339. The next prime is 21154381. The reversal of 21154357 is 75345112.

It is a happy number.

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 21154357 - 2¹¹ = 21152309 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21154387) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5068 + ... + 8245.

It is an arithmetic number, because the mean of its divisors is an integer number (3035592).

Almost surely, 2^21154357 is an apocalyptic number.

It is an amenable number.

21154357 is a deficient number, since it is larger than the sum of its proper divisors (3130379).

21154357 is a wasteful number, since it uses less digits than its factorization.

21154357 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13547.

The product of its digits is 4200, while the sum is 28.

The square root of 21154357 is about 4599.3865895356. The cubic root of 21154357 is about 276.5667352517.

Adding to 21154357 its reverse (75345112), we get a palindrome (96499469).

It can be divided in two parts, 211543 and 57, that added together give a square (211600 = 460²).

The spelling of 21154357 in words is "twenty-one million, one hundred fifty-four thousand, three hundred fifty-seven".