21129442 has 8 divisors (see below), whose sum is σ = 32550876. Its totient is φ = 10279152.

The previous prime is 21129439. The next prime is 21129467. The reversal of 21129442 is 24492112.

It can be written as a sum of positive squares in 2 ways, for example, as 15374241 + 5755201 = 3921^2 + 2399^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 142693 + ... + 142840.

Almost surely, 2^21129442 is an apocalyptic number.

21129442 is a deficient number, since it is larger than the sum of its proper divisors (11421434).

21129442 is a wasteful number, since it uses less digits than its factorization.

21129442 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 285572.

The product of its digits is 1152, while the sum is 25.

The square root of 21129442 is about 4596.6772782087. The cubic root of 21129442 is about 276.4581151191.

The spelling of 21129442 in words is "twenty-one million, one hundred twenty-nine thousand, four hundred forty-two".