21039154 has 4 divisors (see below), whose sum is σ = 31558734. Its totient is φ = 10519576.

The previous prime is 21039143. The next prime is 21039197. The reversal of 21039154 is 45193012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 19562929 + 1476225 = 4423^2 + 1215^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5259787 + ... + 5259790.

Almost surely, 2^21039154 is an apocalyptic number.

21039154 is a deficient number, since it is larger than the sum of its proper divisors (10519580).

21039154 is a wasteful number, since it uses less digits than its factorization.

21039154 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10519579.

The product of its (nonzero) digits is 1080, while the sum is 25.

The square root of 21039154 is about 4586.8457571625. The cubic root of 21039154 is about 276.0637761322.

The spelling of 21039154 in words is "twenty-one million, thirty-nine thousand, one hundred fifty-four".