21540214100 has 36 divisors (see below), whose sum is σ = 46759548864. Its totient is φ = 8612899680.

The previous prime is 21540214093. The next prime is 21540214103. The reversal of 21540214100 is 141204512.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21540214103) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 241877 + ... + 318723.

Almost surely, 2^21540214100 is an apocalyptic number.

21540214100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21540214100 is an abundant number, since it is smaller than the sum of its proper divisors (25219334764).

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

21540214100 is a wasteful number, since it uses less digits than its factorization.

21540214100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79664 (or 79657 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 20.

Adding to 21540214100 its reverse (141204512), we get a palindrome (21681418612).

The spelling of 21540214100 in words is "twenty-one billion, five hundred forty million, two hundred fourteen thousand, one hundred".