101220021 has 48 divisors (see below), whose sum is σ = 172972800. Its totient is φ = 55837440.

The previous prime is 101220013. The next prime is 101220037. The reversal of 101220021 is 120022101.

It is not a de Polignac number, because 101220021 - 2³ = 101220013 is a prime.

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

It is a junction number, because it is equal to n+sod(n) for n = 101219985 and 101220012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (101220001) 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, 384736 + ... + 384998.

It is an arithmetic number, because the mean of its divisors is an integer number (3603600).

Almost surely, 2^101220021 is an apocalyptic number.

It is an amenable number.

101220021 is a deficient number, since it is larger than the sum of its proper divisors (71752779).

101220021 is a wasteful number, since it uses less digits than its factorization.

101220021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 466 (or 463 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

The square root of 101220021 is about 10060.8161199775. The cubic root of 101220021 is about 466.0388705012.

Adding to 101220021 its reverse (120022101), we get a palindrome (221242122).

The spelling of 101220021 in words is "one hundred one million, two hundred twenty thousand, twenty-one".