21490016 has 24 divisors (see below), whose sum is σ = 43110144. Its totient is φ = 10541440.

The previous prime is 21490013. The next prime is 21490031. The reversal of 21490016 is 61009412.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21489973 and 21490000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21490013) 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, 4640 + ... + 8031.

It is an arithmetic number, because the mean of its divisors is an integer number (1796256).

Almost surely, 2^21490016 is an apocalyptic number.

It is an amenable number.

21490016 is an abundant number, since it is smaller than the sum of its proper divisors (21620128).

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

21490016 is a wasteful number, since it uses less digits than its factorization.

21490016 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12734 (or 12726 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 23.

The square root of 21490016 is about 4635.7325203251. The cubic root of 21490016 is about 278.0218398038.

Adding to 21490016 its reverse (61009412), we get a palindrome (82499428).

The spelling of 21490016 in words is "twenty-one million, four hundred ninety thousand, sixteen".