21213613254540 has 48 divisors (see below), whose sum is σ = 67883562415872. Its totient is φ = 4848825886656.

The previous prime is 21213613254521. The next prime is 21213613254577. The reversal of 21213613254540 is 4545231631212.

It is a super-2 number, since 2×21213613254540² (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 15 ways as a sum of consecutive naturals, for example, 25254301074 + ... + 25254301913.

It is an arithmetic number, because the mean of its divisors is an integer number (1414240883664).

Almost surely, 2^{21213613254540} is an apocalyptic number.

21213613254540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21213613254540 is an abundant number, since it is smaller than the sum of its proper divisors (46669949161332).

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

21213613254540 is a wasteful number, since it uses less digits than its factorization.

21213613254540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50508603006 (or 50508603004 counting only the distinct ones).

The product of its (nonzero) digits is 172800, while the sum is 39.

Adding to 21213613254540 its reverse (4545231631212), we get a palindrome (25758844885752).

The spelling of 21213613254540 in words is "twenty-one trillion, two hundred thirteen billion, six hundred thirteen million, two hundred fifty-four thousand, five hundred forty".