21421701798 has 32 divisors (see below), whose sum is σ = 49074460416. Its totient is φ = 6106664928.

The previous prime is 21421701793. The next prime is 21421701841. The reversal of 21421701798 is 89710712412.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21421701793) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 557061 + ... + 594272.

It is an arithmetic number, because the mean of its divisors is an integer number (1533576888).

Almost surely, 2^21421701798 is an apocalyptic number.

21421701798 is an abundant number, since it is smaller than the sum of its proper divisors (27652758618).

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

21421701798 is a wasteful number, since it uses less digits than its factorization.

21421701798 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1151788.

The product of its (nonzero) digits is 56448, while the sum is 42.

The spelling of 21421701798 in words is "twenty-one billion, four hundred twenty-one million, seven hundred one thousand, seven hundred ninety-eight".