20702640 has 80 divisors (see below), whose sum is σ = 73352448. Its totient is φ = 4731648.

The previous prime is 20702639. The next prime is 20702641. The reversal of 20702640 is 4620702.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (20702639) and next prime (20702641).

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (21).

It is not an unprimeable number, because it can be changed into a prime (20702641) 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, 4482 + ... + 7841.

Almost surely, 2^20702640 is an apocalyptic number.

20702640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20702640 is an abundant number, since it is smaller than the sum of its proper divisors (52649808).

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

20702640 is a wasteful number, since it uses less digits than its factorization.

20702640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12346 (or 12340 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 21.

The square root of 20702640 is about 4550.0153845894. The cubic root of 20702640 is about 274.5840101720.

The spelling of 20702640 in words is "twenty million, seven hundred two thousand, six hundred forty".