21690017400 has 96 divisors (see below), whose sum is σ = 67262592240. Its totient is φ = 5781980160.

The previous prime is 21690017399. The next prime is 21690017407. The reversal of 21690017400 is 471009612.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21690017407) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2610052 + ... + 2618348.

Almost surely, 2^21690017400 is an apocalyptic number.

21690017400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21690017400 is an abundant number, since it is smaller than the sum of its proper divisors (45572574840).

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

21690017400 is a wasteful number, since it uses less digits than its factorization.

21690017400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12673 (or 12664 counting only the distinct ones).

The product of its (nonzero) digits is 3024, while the sum is 30.

The spelling of 21690017400 in words is "twenty-one billion, six hundred ninety million, seventeen thousand, four hundred".