21526453998 has 128 divisors (see below), whose sum is σ = 56525322240. Its totient is φ = 5943974400.

The previous prime is 21526453981. The next prime is 21526454041. The reversal of 21526453998 is 89935462512.

21526453998 is a `hidden beast` number, since 2 + 15 + 2 + 6 + 4 + 539 + 98 = 666.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 2106790 + ... + 2116982.

It is an arithmetic number, because the mean of its divisors is an integer number (441604080).

Almost surely, 2^21526453998 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21526453998, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28262661120).

21526453998 is an abundant number, since it is smaller than the sum of its proper divisors (34998868242).

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

21526453998 is a wasteful number, since it uses less digits than its factorization.

21526453998 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10399 (or 10393 counting only the distinct ones).

The product of its digits is 4665600, while the sum is 54.

The spelling of 21526453998 in words is "twenty-one billion, five hundred twenty-six million, four hundred fifty-three thousand, nine hundred ninety-eight".