1220386521 has 4 divisors (see below), whose sum is σ = 1627182032. Its totient is φ = 813591012.

The previous prime is 1220386499. The next prime is 1220386529. The reversal of 1220386521 is 1256830221.

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.

It is not a de Polignac number, because 1220386521 - 2⁶ = 1220386457 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1220386529) 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, 203397751 + ... + 203397756.

It is an arithmetic number, because the mean of its divisors is an integer number (406795508).

Almost surely, 2^1220386521 is an apocalyptic number.

It is an amenable number.

1220386521 is a deficient number, since it is larger than the sum of its proper divisors (406795511).

1220386521 is an equidigital number, since it uses as much as digits as its factorization.

1220386521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 406795510.

The product of its (nonzero) digits is 5760, while the sum is 30.

The square root of 1220386521 is about 34934.0309869903. The cubic root of 1220386521 is about 1068.6425622721.

The spelling of 1220386521 in words is "one billion, two hundred twenty million, three hundred eighty-six thousand, five hundred twenty-one".