1021620731 has 4 divisors (see below), whose sum is σ = 1021737864. Its totient is φ = 1021503600.

The previous prime is 1021620707. The next prime is 1021620737. The reversal of 1021620731 is 1370261201.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1021620731 - 2⁶ = 1021620667 is a prime.

It is a super-2 number, since 2×1021620731² = 2087417836017948722, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1021620697 and 1021620706.

It is not an unprimeable number, because it can be changed into a prime (1021620737) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 44330 + ... + 63311.

It is an arithmetic number, because the mean of its divisors is an integer number (255434466).

Almost surely, 2^1021620731 is an apocalyptic number.

1021620731 is a deficient number, since it is larger than the sum of its proper divisors (117133).

1021620731 is an equidigital number, since it uses as much as digits as its factorization.

1021620731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 117132.

The product of its (nonzero) digits is 504, while the sum is 23.

The square root of 1021620731 is about 31962.8023020511. The cubic root of 1021620731 is about 1007.1555857975.

Adding to 1021620731 its reverse (1370261201), we get a palindrome (2391881932).

The spelling of 1021620731 in words is "one billion, twenty-one million, six hundred twenty thousand, seven hundred thirty-one".