21601621515252 has 24 divisors (see below), whose sum is σ = 52029712037632. Its totient is φ = 6968265004800.

The previous prime is 21601621515241. The next prime is 21601621515329. The reversal of 21601621515252 is 25251512610612.

It is a happy number.

It is a super-2 number, since 2×21601621515252² (a number of 27 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21601621515252.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 29034437149 + ... + 29034437892.

Almost surely, 2^{21601621515252} is an apocalyptic number.

It is an amenable number.

21601621515252 is an abundant number, since it is smaller than the sum of its proper divisors (30428090522380).

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

21601621515252 is a wasteful number, since it uses less digits than its factorization.

21601621515252 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58068875079 (or 58068875077 counting only the distinct ones).

The product of its (nonzero) digits is 72000, while the sum is 39.

The spelling of 21601621515252 in words is "twenty-one trillion, six hundred one billion, six hundred twenty-one million, five hundred fifteen thousand, two hundred fifty-two".