21501041405450 has 24 divisors (see below), whose sum is σ = 40037537936172. Its totient is φ = 8590609912320.

The previous prime is 21501041405419. The next prime is 21501041405471. The reversal of 21501041405450 is 5450414010512.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 17239859672281 + 4261181733169 = 4152091^2 + 2064263^2 .

It is a super-2 number, since 2×21501041405450² (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 11 ways as a sum of consecutive naturals, for example, 245121959 + ... + 245209658.

Almost surely, 2^{21501041405450} is an apocalyptic number.

21501041405450 is a deficient number, since it is larger than the sum of its proper divisors (18536496530722).

21501041405450 is a wasteful number, since it uses less digits than its factorization.

21501041405450 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 490332506 (or 490332501 counting only the distinct ones).

The product of its (nonzero) digits is 16000, while the sum is 32.

Adding to 21501041405450 its reverse (5450414010512), we get a palindrome (26951455415962).

The spelling of 21501041405450 in words is "twenty-one trillion, five hundred one billion, forty-one million, four hundred five thousand, four hundred fifty".