20420745 has 8 divisors (see below), whose sum is σ = 32673216. Its totient is φ = 10891056.

The previous prime is 20420681. The next prime is 20420759. The reversal of 20420745 is 54702402.

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

It is not a de Polignac number, because 20420745 - 2⁶ = 20420681 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 680677 + ... + 680706.

It is an arithmetic number, because the mean of its divisors is an integer number (4084152).

Almost surely, 2^20420745 is an apocalyptic number.

It is an amenable number.

20420745 is a deficient number, since it is larger than the sum of its proper divisors (12252471).

20420745 is a wasteful number, since it uses less digits than its factorization.

20420745 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1361391.

The product of its (nonzero) digits is 2240, while the sum is 24.

The square root of 20420745 is about 4518.9318428142. The cubic root of 20420745 is about 273.3320303659.

The spelling of 20420745 in words is "twenty million, four hundred twenty thousand, seven hundred forty-five".