20645670 has 32 divisors (see below), whose sum is σ = 49916160. Its totient is φ = 5464800.

The previous prime is 20645579. The next prime is 20645671. The reversal of 20645670 is 7654602.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20645671) 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, 1695 + ... + 6645.

It is an arithmetic number, because the mean of its divisors is an integer number (1559880).

Almost surely, 2^20645670 is an apocalyptic number.

20645670 is an abundant number, since it is smaller than the sum of its proper divisors (29270490).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20645670 is a wasteful number, since it uses less digits than its factorization.

20645670 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5100.

The product of its (nonzero) digits is 10080, while the sum is 30.

The square root of 20645670 is about 4543.7506533700. The cubic root of 20645670 is about 274.3319099245.

The spelling of 20645670 in words is "twenty million, six hundred forty-five thousand, six hundred seventy".