21702149 has 12 divisors (see below), whose sum is σ = 26731404. Its totient is φ = 17506944.

The previous prime is 21702103. The next prime is 21702157. The reversal of 21702149 is 94120712.

It can be written as a sum of positive squares in 2 ways, for example, as 17581249 + 4120900 = 4193^2 + 2030^2 .

It is not a de Polignac number, because 21702149 - 2²⁰ = 20653573 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21702049) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 12194 + ... + 13859.

It is an arithmetic number, because the mean of its divisors is an integer number (2227617).

Almost surely, 2^21702149 is an apocalyptic number.

It is an amenable number.

21702149 is a deficient number, since it is larger than the sum of its proper divisors (5029255).

21702149 is a wasteful number, since it uses less digits than its factorization.

21702149 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26084 (or 26077 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 26.

The square root of 21702149 is about 4658.5565360957. The cubic root of 21702149 is about 278.9336524275.

The spelling of 21702149 in words is "twenty-one million, seven hundred two thousand, one hundred forty-nine".