21501242 has 8 divisors (see below), whose sum is σ = 36859296. Its totient is φ = 9214812.

The previous prime is 21501241. The next prime is 21501253. The reversal of 21501242 is 24210512.

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 21501242.

It is not an unprimeable number, because it can be changed into a prime (21501241) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 767888 + ... + 767915.

It is an arithmetic number, because the mean of its divisors is an integer number (4607412).

Almost surely, 2^21501242 is an apocalyptic number.

21501242 is a deficient number, since it is larger than the sum of its proper divisors (15358054).

21501242 is a wasteful number, since it uses less digits than its factorization.

21501242 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1535812.

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

The square root of 21501242 is about 4636.9431741181. The cubic root of 21501242 is about 278.0702425887.

Adding to 21501242 its reverse (24210512), we get a palindrome (45711754).

The spelling of 21501242 in words is "twenty-one million, five hundred one thousand, two hundred forty-two".