1201100021 has 4 divisors (see below), whose sum is σ = 1310290944. Its totient is φ = 1091909100.

The previous prime is 1201099981. The next prime is 1201100023. The reversal of 1201100021 is 1200011021.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1200011021 = 11 ⋅109091911.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1201100021 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1201099981 and 1201100008.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1201100023) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 54595445 + ... + 54595466.

It is an arithmetic number, because the mean of its divisors is an integer number (327572736).

Almost surely, 2^1201100021 is an apocalyptic number.

1201100021 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1201100021 is a deficient number, since it is larger than the sum of its proper divisors (109190923).

1201100021 is a wasteful number, since it uses less digits than its factorization.

1201100021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 109190922.

The product of its (nonzero) digits is 4, while the sum is 8.

The square root of 1201100021 is about 34656.8899499075. The cubic root of 1201100021 is about 1062.9831774434.

Adding to 1201100021 its reverse (1200011021), we get a palindrome (2401111042).

It can be divided in two parts, 12011000 and 21, that added together give a palindrome (12011021).

The spelling of 1201100021 in words is "one billion, two hundred one million, one hundred thousand, twenty-one".