420209621 has 16 divisors (see below), whose sum is σ = 479881584. Its totient is φ = 364514304.

The previous prime is 420209593. The next prime is 420209633. The reversal of 420209621 is 126902024.

It can be written as a sum of positive squares in 8 ways, for example, as 50608996 + 369600625 = 7114^2 + 19225^2 .

It is a cyclic number.

It is not a de Polignac number, because 420209621 - 2¹⁸ = 419947477 is a prime.

It is a super-2 number, since 2×420209621² = 353152251161927282, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (420209641) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 222935 + ... + 224811.

It is an arithmetic number, because the mean of its divisors is an integer number (29992599).

Almost surely, 2^420209621 is an apocalyptic number.

It is an amenable number.

420209621 is a deficient number, since it is larger than the sum of its proper divisors (59671963).

420209621 is a wasteful number, since it uses less digits than its factorization.

420209621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2920.

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

The square root of 420209621 is about 20499.0151226833. The cubic root of 420209621 is about 749.0118072795.

The spelling of 420209621 in words is "four hundred twenty million, two hundred nine thousand, six hundred twenty-one".