21891225737640 has 256 divisors, whose sum is σ = 75214016317440. Its totient is φ = 4993156224000.

The previous prime is 21891225737621. The next prime is 21891225737677. The reversal of 21891225737640 is 4673752219812.

It is a super-2 number, since 2×21891225737640² (a number of 27 digits) contains 22 as substring.

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, 1712788050 + ... + 1712800830.

It is an arithmetic number, because the mean of its divisors is an integer number (293804751240).

It is a 1-persistent number, because it is pandigital, but 2⋅21891225737640 = 43782451475280 is not.

Almost surely, 2^{21891225737640} is an apocalyptic number.

21891225737640 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 21891225737640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37607008158720).

21891225737640 is an abundant number, since it is smaller than the sum of its proper divisors (53322790579800).

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

21891225737640 is a wasteful number, since it uses less digits than its factorization.

21891225737640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16944 (or 16940 counting only the distinct ones).

The product of its (nonzero) digits is 10160640, while the sum is 57.

The spelling of 21891225737640 in words is "twenty-one trillion, eight hundred ninety-one billion, two hundred twenty-five million, seven hundred thirty-seven thousand, six hundred forty".