221620021631 has 8 divisors (see below), whose sum is σ = 222865533984. Its totient is φ = 220377749760.

The previous prime is 221620021549. The next prime is 221620021643. The reversal of 221620021631 is 136120026122.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 221620021631 - 2¹⁴ = 221620005247 is a prime.

It is a super-2 number, since 2×221620021631² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 221620021631.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221620021661) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 672890 + ... + 946583.

It is an arithmetic number, because the mean of its divisors is an integer number (27858191748).

Almost surely, 2^221620021631 is an apocalyptic number.

221620021631 is a deficient number, since it is larger than the sum of its proper divisors (1245512353).

221620021631 is a wasteful number, since it uses less digits than its factorization.

221620021631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1620241.

The product of its (nonzero) digits is 1728, while the sum is 26.

Adding to 221620021631 its reverse (136120026122), we get a palindrome (357740047753).

The spelling of 221620021631 in words is "two hundred twenty-one billion, six hundred twenty million, twenty-one thousand, six hundred thirty-one".