21089145420 has 240 divisors, whose sum is σ = 76361237568. Its totient is φ = 4772390400.

The previous prime is 21089145397. The next prime is 21089145479. The reversal of 21089145420 is 2454198012.

21089145420 is a `hidden beast` number, since 2 + 10 + 89 + 145 + 420 = 666.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

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

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 1136134 + ... + 1154546.

Almost surely, 2^21089145420 is an apocalyptic number.

21089145420 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 21089145420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38180618784).

21089145420 is an abundant number, since it is smaller than the sum of its proper divisors (55272092148).

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

21089145420 is a wasteful number, since it uses less digits than its factorization.

21089145420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18542 (or 18531 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 36.

The spelling of 21089145420 in words is "twenty-one billion, eighty-nine million, one hundred forty-five thousand, four hundred twenty".