21506476 has 6 divisors (see below), whose sum is σ = 37636340. Its totient is φ = 10753236.

The previous prime is 21506473. The next prime is 21506483. The reversal of 21506476 is 67460512.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21506473) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2688306 + ... + 2688313.

Almost surely, 2^21506476 is an apocalyptic number.

It is an amenable number.

21506476 is a deficient number, since it is larger than the sum of its proper divisors (16129864).

21506476 is a wasteful number, since it uses less digits than its factorization.

21506476 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5376623 (or 5376621 counting only the distinct ones).

The product of its (nonzero) digits is 10080, while the sum is 31.

The square root of 21506476 is about 4637.5075202095. The cubic root of 21506476 is about 278.0928041004.

Adding to 21506476 its reverse (67460512), we get a palindrome (88966988).

The spelling of 21506476 in words is "twenty-one million, five hundred six thousand, four hundred seventy-six".