21629400 has 192 divisors, whose sum is σ = 74995200. Its totient is φ = 5122560.

The previous prime is 21629393. The next prime is 21629401. The reversal of 21629400 is 492612.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21629401) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 366571 + ... + 366629.

It is an arithmetic number, because the mean of its divisors is an integer number (390600).

Almost surely, 2^21629400 is an apocalyptic number.

21629400 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 21629400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37497600).

21629400 is an abundant number, since it is smaller than the sum of its proper divisors (53365800).

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

21629400 is a wasteful number, since it uses less digits than its factorization.

21629400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 138 (or 129 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 24.

The square root of 21629400 is about 4650.7418763032. The cubic root of 21629400 is about 278.6216270953.

It can be divided in two parts, 216 and 29400, that multiplied together give a square (6350400 = 2520²).

The spelling of 21629400 in words is "twenty-one million, six hundred twenty-nine thousand, four hundred".