421220661 has 4 divisors (see below), whose sum is σ = 561627552. Its totient is φ = 280813772.

The previous prime is 421220659. The next prime is 421220669. The reversal of 421220661 is 166022124.

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 a cyclic number.

It is not a de Polignac number, because 421220661 - 2¹ = 421220659 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (421220669) 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, 70203441 + ... + 70203446.

It is an arithmetic number, because the mean of its divisors is an integer number (140406888).

Almost surely, 2^421220661 is an apocalyptic number.

It is an amenable number.

421220661 is a deficient number, since it is larger than the sum of its proper divisors (140406891).

421220661 is a wasteful number, since it uses less digits than its factorization.

421220661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 140406890.

The product of its (nonzero) digits is 1152, while the sum is 24.

The square root of 421220661 is about 20523.6610038268. The cubic root of 421220661 is about 749.6120429092.

Adding to 421220661 its reverse (166022124), we get a palindrome (587242785).

It can be divided in two parts, 42 and 1220661, that added together give a triangular number (1220703 = T₁₅₆₂).

The spelling of 421220661 in words is "four hundred twenty-one million, two hundred twenty thousand, six hundred sixty-one".