20953840 has 40 divisors (see below), whose sum is σ = 50041440. Its totient is φ = 8153856.

The previous prime is 20953831. The next prime is 20953841. The reversal of 20953840 is 4835902.

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20953841) 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, 580 + ... + 6499.

It is an arithmetic number, because the mean of its divisors is an integer number (1251036).

Almost surely, 2^20953840 is an apocalyptic number.

20953840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20953840 is an abundant number, since it is smaller than the sum of its proper divisors (29087600).

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

20953840 is a wasteful number, since it uses less digits than its factorization.

20953840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7129 (or 7123 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 31.

The square root of 20953840 is about 4577.5364553436. The cubic root of 20953840 is about 275.6901234085.

The spelling of 20953840 in words is "twenty million, nine hundred fifty-three thousand, eight hundred forty".