21240178704 has 30 divisors (see below), whose sum is σ = 59443000526. Its totient is φ = 7080059520.

The previous prime is 21240178697. The next prime is 21240178741. The reversal of 21240178704 is 40787104212.

It can be written as a sum of positive squares in only one way, i.e., 21152793600 + 87385104 = 145440^2 + 9348^2 .

It is a super-2 number, since 2×21240178704² (a number of 21 digits) contains 22 as substring.

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 5 ways as a sum of consecutive naturals, for example, 73750477 + ... + 73750764.

Almost surely, 2^21240178704 is an apocalyptic number.

21240178704 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21240178704 is an abundant number, since it is smaller than the sum of its proper divisors (38202821822).

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

21240178704 is a wasteful number, since it uses less digits than its factorization.

21240178704 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 147501255 (or 147501246 counting only the distinct ones).

The product of its (nonzero) digits is 25088, while the sum is 36.

The spelling of 21240178704 in words is "twenty-one billion, two hundred forty million, one hundred seventy-eight thousand, seven hundred four".