21674709 has 60 divisors (see below), whose sum is σ = 38843904. Its totient is φ = 12002256.

The previous prime is 21674699. The next prime is 21674749. The reversal of 21674709 is 90747612.

21674709 = T₂₉₅ + T₂₉₆ + ... + T₅₃₇.

It is a happy number.

It is not a de Polignac number, because 21674709 - 2⁴ = 21674693 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21674749) by changing a digit.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 170604 + ... + 170730.

Almost surely, 2^21674709 is an apocalyptic number.

It is an amenable number.

21674709 is a deficient number, since it is larger than the sum of its proper divisors (17169195).

21674709 is a wasteful number, since it uses less digits than its factorization.

21674709 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 196 (or 180 counting only the distinct ones).

The product of its (nonzero) digits is 21168, while the sum is 36.

The square root of 21674709 is about 4655.6104862843. The cubic root of 21674709 is about 278.8160424533.

The spelling of 21674709 in words is "twenty-one million, six hundred seventy-four thousand, seven hundred nine".