21515142 has 16 divisors (see below), whose sum is σ = 46942272. Its totient is φ = 6519720.

The previous prime is 21515113. The next prime is 21515159. The reversal of 21515142 is 24151512.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 162928 + ... + 163059.

It is an arithmetic number, because the mean of its divisors is an integer number (2933892).

Almost surely, 2^21515142 is an apocalyptic number.

21515142 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21515142 is an abundant number, since it is smaller than the sum of its proper divisors (25427130).

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

21515142 is a wasteful number, since it uses less digits than its factorization.

21515142 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 326003.

The product of its digits is 400, while the sum is 21.

The square root of 21515142 is about 4638.4417642135. The cubic root of 21515142 is about 278.1301514343.

Adding to 21515142 its reverse (24151512), we get a palindrome (45666654).

The spelling of 21515142 in words is "twenty-one million, five hundred fifteen thousand, one hundred forty-two".