21680274 has 64 divisors (see below), whose sum is σ = 54577152. Its totient is φ = 5577600.

The previous prime is 21680257. The next prime is 21680279. The reversal of 21680274 is 47208612.

It is not an unprimeable number, because it can be changed into a prime (21680279) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 77014 + ... + 77294.

It is an arithmetic number, because the mean of its divisors is an integer number (852768).

Almost surely, 2^21680274 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21680274, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27288576).

21680274 is an abundant number, since it is smaller than the sum of its proper divisors (32896878).

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

21680274 is a wasteful number, since it uses less digits than its factorization.

21680274 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 471.

The product of its (nonzero) digits is 5376, while the sum is 30.

The square root of 21680274 is about 4656.2081139056. The cubic root of 21680274 is about 278.8399024969.

Adding to 21680274 its reverse (47208612), we get a palindrome (68888886).

The spelling of 21680274 in words is "twenty-one million, six hundred eighty thousand, two hundred seventy-four".