21398491548 has 240 divisors, whose sum is σ = 65829544704. Its totient is φ = 5958437760.

The previous prime is 21398491547. The next prime is 21398491571. The reversal of 21398491548 is 84519489312.

It is a happy number.

21398491548 is a `hidden beast` number, since 2 + 1 + 3 + 9 + 8 + 4 + 91 + 548 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a junction number, because it is equal to n+sod(n) for n = 21398491494 and 21398491503.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21398491547) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 22595611 + ... + 22596557.

Almost surely, 2^21398491548 is an apocalyptic number.

21398491548 is a gapful number since it is divisible by the number (28) 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 21398491548, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32914772352).

21398491548 is an abundant number, since it is smaller than the sum of its proper divisors (44431053156).

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

21398491548 is an frugal number, since it uses more digits than its factorization.

21398491548 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1026 (or 1000 counting only the distinct ones).

The product of its digits is 2488320, while the sum is 54.

The spelling of 21398491548 in words is "twenty-one billion, three hundred ninety-eight million, four hundred ninety-one thousand, five hundred forty-eight".