21490006 has 16 divisors (see below), whose sum is σ = 35233920. Its totient is φ = 9786240.

The previous prime is 21489997. The next prime is 21490009. The reversal of 21490006 is 60009412.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21490009) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9141 + ... + 11248.

It is an arithmetic number, because the mean of its divisors is an integer number (2202120).

Almost surely, 2^21490006 is an apocalyptic number.

21490006 is a deficient number, since it is larger than the sum of its proper divisors (13743914).

21490006 is a wasteful number, since it uses less digits than its factorization.

21490006 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20439.

The product of its (nonzero) digits is 432, while the sum is 22.

The square root of 21490006 is about 4635.7314417468. The cubic root of 21490006 is about 278.0217966796.

Adding to 21490006 its reverse (60009412), we get a palindrome (81499418).

The spelling of 21490006 in words is "twenty-one million, four hundred ninety thousand, six".