1221010101 has 48 divisors (see below), whose sum is σ = 1852824064. Its totient is φ = 774116352.

The previous prime is 1221010097. The next prime is 1221010103. The reversal of 1221010101 is 1010101221.

It is a happy number.

It is not a de Polignac number, because 1221010101 - 2² = 1221010097 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a Duffinian number.

1221010101 is a modest number, since divided by 10101 gives 1221 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221010103) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3326820 + ... + 3327186.

Almost surely, 2^1221010101 is an apocalyptic number.

It is an amenable number.

1221010101 is a deficient number, since it is larger than the sum of its proper divisors (631813963).

1221010101 is a wasteful number, since it uses less digits than its factorization.

1221010101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 610 (or 607 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

The square root of 1221010101 is about 34942.9549551837. The cubic root of 1221010101 is about 1068.8245457801.

Adding to 1221010101 its reverse (1010101221), we get a palindrome (2231111322).

The spelling of 1221010101 in words is "one billion, two hundred twenty-one million, ten thousand, one hundred one".