21716402 has 8 divisors (see below), whose sum is σ = 32678316. Its totient is φ = 10823632.

The previous prime is 21716381. The next prime is 21716407. The reversal of 21716402 is 20461712.

It can be written as a sum of positive squares in 2 ways, for example, as 17799961 + 3916441 = 4219^2 + 1979^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (21716407) 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, 16493 + ... + 17760.

Almost surely, 2^21716402 is an apocalyptic number.

21716402 is a deficient number, since it is larger than the sum of its proper divisors (10961914).

21716402 is a wasteful number, since it uses less digits than its factorization.

21716402 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34572.

The product of its (nonzero) digits is 672, while the sum is 23.

The square root of 21716402 is about 4660.0860507076. The cubic root of 21716402 is about 278.9947027767.

The spelling of 21716402 in words is "twenty-one million, seven hundred sixteen thousand, four hundred two".