20645969 has 8 divisors (see below), whose sum is σ = 21365760. Its totient is φ = 19929600.

The previous prime is 20645957. The next prime is 20645981. The reversal of 20645969 is 96954602.

It is an interprime number because it is at equal distance from previous prime (20645957) and next prime (20645981).

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 20645969 - 2¹⁶ = 20580433 is a prime.

It is a super-2 number, since 2×20645969² = 852512071897922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20645069) 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, 19352 + ... + 20390.

It is an arithmetic number, because the mean of its divisors is an integer number (2670720).

Almost surely, 2^20645969 is an apocalyptic number.

It is an amenable number.

20645969 is a deficient number, since it is larger than the sum of its proper divisors (719791).

20645969 is a wasteful number, since it uses less digits than its factorization.

20645969 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1711.

The product of its (nonzero) digits is 116640, while the sum is 41.

The square root of 20645969 is about 4543.7835555845. The cubic root of 20645969 is about 274.3332342513. Note that the first 3 decimals are identical.

The spelling of 20645969 in words is "twenty million, six hundred forty-five thousand, nine hundred sixty-nine".