21154149 has 8 divisors (see below), whose sum is σ = 31339520. Its totient is φ = 14102748.

The previous prime is 21154141. The next prime is 21154153. The reversal of 21154149 is 94145112.

It is not a de Polignac number, because 21154149 - 2³ = 21154141 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 783487 = 21154149 / (2 + 1 + 1 + 5 + 4 + 1 + 4 + 9).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21154141) 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, 391717 + ... + 391770.

It is an arithmetic number, because the mean of its divisors is an integer number (3917440).

Almost surely, 2^21154149 is an apocalyptic number.

It is an amenable number.

21154149 is a deficient number, since it is larger than the sum of its proper divisors (10185371).

21154149 is an equidigital number, since it uses as much as digits as its factorization.

21154149 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 783496 (or 783490 counting only the distinct ones).

The product of its digits is 1440, while the sum is 27.

The square root of 21154149 is about 4599.3639777691. The cubic root of 21154149 is about 276.5658288022.

The spelling of 21154149 in words is "twenty-one million, one hundred fifty-four thousand, one hundred forty-nine".