21154339 has 2 divisors, whose sum is σ = 21154340. Its totient is φ = 21154338.

The previous prime is 21154283. The next prime is 21154381. The reversal of 21154339 is 93345112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21154339 - 2¹¹ = 21152291 is a prime.

It is not a weakly prime, because it can be changed into another prime (21154039) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10577169 + 10577170.

It is an arithmetic number, because the mean of its divisors is an integer number (10577170).

Almost surely, 2^21154339 is an apocalyptic number.

21154339 is a deficient number, since it is larger than the sum of its proper divisors (1).

21154339 is an equidigital number, since it uses as much as digits as its factorization.

21154339 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3240, while the sum is 28.

The square root of 21154339 is about 4599.3846327525. The cubic root of 21154339 is about 276.5666568092.

The spelling of 21154339 in words is "twenty-one million, one hundred fifty-four thousand, three hundred thirty-nine".