21670553 has 8 divisors (see below), whose sum is σ = 22084608. Its totient is φ = 21260304.

The previous prime is 21670543. The next prime is 21670559. The reversal of 21670553 is 35507612.

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

It is a cyclic number.

It is not a de Polignac number, because 21670553 - 2⁶ = 21670489 is a prime.

It is a super-2 number, since 2×21670553² = 939225734651618, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21670559) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12200 + ... + 13862.

It is an arithmetic number, because the mean of its divisors is an integer number (2760576).

Almost surely, 2^21670553 is an apocalyptic number.

It is an amenable number.

21670553 is a deficient number, since it is larger than the sum of its proper divisors (414055).

21670553 is a wasteful number, since it uses less digits than its factorization.

21670553 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1903.

The product of its (nonzero) digits is 6300, while the sum is 29.

The square root of 21670553 is about 4655.1641217040. The cubic root of 21670553 is about 278.7982208601.

The spelling of 21670553 in words is "twenty-one million, six hundred seventy thousand, five hundred fifty-three".