21512214 has 12 divisors (see below), whose sum is σ = 46609836. Its totient is φ = 7170732.

The previous prime is 21512213. The next prime is 21512263. The reversal of 21512214 is 41221512.

It is a Harshad number since it is a multiple of its sum of digits (18), and also a Moran number because the ratio is a prime number: 1195123 = 21512214 / (2 + 1 + 5 + 1 + 2 + 2 + 1 + 4).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21512213) by changing a digit.

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 in 5 ways as a sum of consecutive naturals, for example, 597544 + ... + 597579.

It is an arithmetic number, because the mean of its divisors is an integer number (3884153).

Almost surely, 2^21512214 is an apocalyptic number.

21512214 is an abundant number, since it is smaller than the sum of its proper divisors (25097622).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21512214 is a wasteful number, since it uses less digits than its factorization.

21512214 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1195131 (or 1195128 counting only the distinct ones).

The product of its digits is 160, while the sum is 18.

The square root of 21512214 is about 4638.1261302384. The cubic root of 21512214 is about 278.1175339325.

Adding to 21512214 its reverse (41221512), we get a palindrome (62733726).

The spelling of 21512214 in words is "twenty-one million, five hundred twelve thousand, two hundred fourteen".