20890477440 has 384 divisors, whose sum is σ = 84460259520. Its totient is φ = 4658135040.

The previous prime is 20890477429. The next prime is 20890477441. The reversal of 20890477440 is 4477409802.

It is a tau number, because it is divible by the number of its divisors (384).

It is a super-2 number, since 2×20890477440² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20890477441) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1646802 + ... + 1659438.

Almost surely, 2^20890477440 is an apocalyptic number.

20890477440 is a gapful number since it is divisible by the number (20) 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 20890477440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42230129760).

20890477440 is an abundant number, since it is smaller than the sum of its proper divisors (63569782080).

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

20890477440 is a wasteful number, since it uses less digits than its factorization.

20890477440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12710 (or 12695 counting only the distinct ones).

The product of its (nonzero) digits is 451584, while the sum is 45.

The spelling of 20890477440 in words is "twenty billion, eight hundred ninety million, four hundred seventy-seven thousand, four hundred forty".