21405723000 has 256 divisors, whose sum is σ = 70878412800. Its totient is φ = 5363366400.

The previous prime is 21405722977. The next prime is 21405723061. The reversal of 21405723000 is 32750412.

It is a Harshad number since it is a multiple of its sum of digits (24).

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, 7237522 + ... + 7240478.

It is an arithmetic number, because the mean of its divisors is an integer number (276868800).

Almost surely, 2^21405723000 is an apocalyptic number.

21405723000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21405723000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35439206400).

21405723000 is an abundant number, since it is smaller than the sum of its proper divisors (49472689800).

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

21405723000 is a wasteful number, since it uses less digits than its factorization.

21405723000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3127 (or 3113 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 24.

The spelling of 21405723000 in words is "twenty-one billion, four hundred five million, seven hundred twenty-three thousand".