21512042 has 8 divisors (see below), whose sum is σ = 32296836. Its totient is φ = 10746432.

The previous prime is 21512033. The next prime is 21512053. The reversal of 21512042 is 24021512.

It can be written as a sum of positive squares in 2 ways, for example, as 20529961 + 982081 = 4531^2 + 991^2 .

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

It is a self number, because there is not a number n which added to its sum of digits gives 21512042.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1553 + ... + 6740.

Almost surely, 2^21512042 is an apocalyptic number.

21512042 is a deficient number, since it is larger than the sum of its proper divisors (10784794).

21512042 is a wasteful number, since it uses less digits than its factorization.

21512042 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9592.

The product of its (nonzero) digits is 160, while the sum is 17.

The square root of 21512042 is about 4638.1075882304. The cubic root of 21512042 is about 278.1167927048.

Adding to 21512042 its reverse (24021512), we get a palindrome (45533554).

The spelling of 21512042 in words is "twenty-one million, five hundred twelve thousand, forty-two".