21670197 has 16 divisors (see below), whose sum is σ = 29855232. Its totient is φ = 13970880.

The previous prime is 21670183. The next prime is 21670199. The reversal of 21670197 is 79107612.

It is not a de Polignac number, because 21670197 - 2⁷ = 21670069 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21670199) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 21372 + ... + 22362.

It is an arithmetic number, because the mean of its divisors is an integer number (1865952).

Almost surely, 2^21670197 is an apocalyptic number.

It is an amenable number.

21670197 is a deficient number, since it is larger than the sum of its proper divisors (8185035).

21670197 is a wasteful number, since it uses less digits than its factorization.

21670197 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1228.

The product of its (nonzero) digits is 5292, while the sum is 33.

The square root of 21670197 is about 4655.1258844418. The cubic root of 21670197 is about 278.7966941692.

The spelling of 21670197 in words is "twenty-one million, six hundred seventy thousand, one hundred ninety-seven".