21621201004026 has 96 divisors (see below), whose sum is σ = 53423005800528. Its totient is φ = 6260649246720.

The previous prime is 21621201004003. The next prime is 21621201004057. The reversal of 21621201004026 is 62040010212612.

21621201004026 is a `hidden beast` number, since 2 + 1 + 621 + 2 + 0 + 10 + 0 + 4 + 0 + 26 = 666.

It can be written as a sum of positive squares in 8 ways, for example, as 15080011123401 + 6541189880625 = 3883299^2 + 2557575^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 36145810 + ... + 36739106.

Almost surely, 2^{21621201004026} is an apocalyptic number.

21621201004026 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 21621201004026, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26711502900264).

21621201004026 is an abundant number, since it is smaller than the sum of its proper divisors (31801804796502).

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

21621201004026 is a wasteful number, since it uses less digits than its factorization.

21621201004026 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 602496 (or 602493 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

Adding to 21621201004026 its reverse (62040010212612), we get a palindrome (83661211216638).

The spelling of 21621201004026 in words is "twenty-one trillion, six hundred twenty-one billion, two hundred one million, four thousand, twenty-six".