21680142 has 32 divisors (see below), whose sum is σ = 47520000. Its totient is φ = 6539520.

The previous prime is 21680101. The next prime is 21680143. The reversal of 21680142 is 24108612.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21680143) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16734 + ... + 17982.

It is an arithmetic number, because the mean of its divisors is an integer number (1485000).

Almost surely, 2^21680142 is an apocalyptic number.

21680142 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21680142 is an abundant number, since it is smaller than the sum of its proper divisors (25839858).

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

21680142 is a wasteful number, since it uses less digits than its factorization.

21680142 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1528.

The product of its (nonzero) digits is 768, while the sum is 24.

The square root of 21680142 is about 4656.1939392598. The cubic root of 21680142 is about 278.8393365916.

Adding to 21680142 its reverse (24108612), we get a palindrome (45788754).

The spelling of 21680142 in words is "twenty-one million, six hundred eighty thousand, one hundred forty-two".