1420420721 has 4 divisors (see below), whose sum is σ = 1420496100. Its totient is φ = 1420345344.

The previous prime is 1420420709. The next prime is 1420420733. The reversal of 1420420721 is 1270240241.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is an interprime number because it is at equal distance from previous prime (1420420709) and next prime (1420420733).

It can be written as a sum of positive squares in 2 ways, for example, as 874030096 + 546390625 = 29564^2 + 23375^2 .

It is a cyclic number.

It is not a de Polignac number, because 1420420721 - 2²² = 1416226417 is a prime.

It is a super-3 number, since 3×1420420721³ (a number of 28 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1420420021) 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, 18545 + ... + 56433.

It is an arithmetic number, because the mean of its divisors is an integer number (355124025).

Almost surely, 2^1420420721 is an apocalyptic number.

It is an amenable number.

1420420721 is a deficient number, since it is larger than the sum of its proper divisors (75379).

1420420721 is an equidigital number, since it uses as much as digits as its factorization.

1420420721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75378.

The product of its (nonzero) digits is 896, while the sum is 23.

The square root of 1420420721 is about 37688.4693374512. The cubic root of 1420420721 is about 1124.1018598878.

Adding to 1420420721 its reverse (1270240241), we get a palindrome (2690660962).

The spelling of 1420420721 in words is "one billion, four hundred twenty million, four hundred twenty thousand, seven hundred twenty-one".