21677149 has 4 divisors (see below), whose sum is σ = 23344636. Its totient is φ = 20009664.

The previous prime is 21677141. The next prime is 21677167. The reversal of 21677149 is 94177612.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2229049 + 19448100 = 1493^2 + 4410^2 .

It is a cyclic number.

It is not a de Polignac number, because 21677149 - 2³ = 21677141 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21677141) 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, 833724 + ... + 833749.

It is an arithmetic number, because the mean of its divisors is an integer number (5836159).

Almost surely, 2^21677149 is an apocalyptic number.

It is an amenable number.

21677149 is a deficient number, since it is larger than the sum of its proper divisors (1667487).

21677149 is a wasteful number, since it uses less digits than its factorization.

21677149 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1667486.

The product of its digits is 21168, while the sum is 37.

The square root of 21677149 is about 4655.8725283238. The cubic root of 21677149 is about 278.8265045025.

It can be divided in two parts, 2167 and 7149, that added together give a triangular number (9316 = T₁₃₆).

The spelling of 21677149 in words is "twenty-one million, six hundred seventy-seven thousand, one hundred forty-nine".