20747664 has 100 divisors (see below), whose sum is σ = 68658304. Its totient is φ = 5925312.

The previous prime is 20747663. The next prime is 20747719. The reversal of 20747664 is 46674702.

It is a super-2 number, since 2×20747664² = 860931122913792, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (20747663) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 7929 + ... + 10215.

Almost surely, 2^20747664 is an apocalyptic number.

20747664 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20747664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34329152).

20747664 is an abundant number, since it is smaller than the sum of its proper divisors (47910640).

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

20747664 is a wasteful number, since it uses less digits than its factorization.

20747664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2314 (or 2299 counting only the distinct ones).

The product of its (nonzero) digits is 56448, while the sum is 36.

The square root of 20747664 is about 4554.9603730439. The cubic root of 20747664 is about 274.7829206982.

The spelling of 20747664 in words is "twenty million, seven hundred forty-seven thousand, six hundred sixty-four".