1221540252201 has 64 divisors (see below), whose sum is σ = 1928745043200. Its totient is φ = 761423781888.

The previous prime is 1221540252193. The next prime is 1221540252217. The reversal of 1221540252201 is 1022520451221.

1221540252201 is a `hidden beast` number, since 1 + 2 + 2 + 1 + 5 + 402 + 52 + 201 = 666.

It is not a de Polignac number, because 1221540252201 - 2³ = 1221540252193 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (1221540252301) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 90123841 + ... + 90137393.

It is an arithmetic number, because the mean of its divisors is an integer number (30136641300).

Almost surely, 2^{1221540252201} is an apocalyptic number.

It is an amenable number.

1221540252201 is a deficient number, since it is larger than the sum of its proper divisors (707204790999).

1221540252201 is a wasteful number, since it uses less digits than its factorization.

1221540252201 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14855 (or 14849 counting only the distinct ones).

The product of its (nonzero) digits is 3200, while the sum is 27.

It can be divided in two parts, 1221540 and 252201, that added together give a palindrome (1473741).

The spelling of 1221540252201 in words is "one trillion, two hundred twenty-one billion, five hundred forty million, two hundred fifty-two thousand, two hundred one".