420902721 has 6 divisors (see below), whose sum is σ = 607970610. Its totient is φ = 280601808.

The previous prime is 420902707. The next prime is 420902731. The reversal of 420902721 is 127209024.

It can be written as a sum of positive squares in only one way, i.e., 333573696 + 87329025 = 18264^2 + 9345^2 .

It is a de Polignac number, because none of the positive numbers 2^k-420902721 is a prime.

It is not an unprimeable number, because it can be changed into a prime (420902701) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 23383476 + ... + 23383493.

It is an arithmetic number, because the mean of its divisors is an integer number (101328435).

Almost surely, 2^420902721 is an apocalyptic number.

It is an amenable number.

420902721 is a deficient number, since it is larger than the sum of its proper divisors (187067889).

420902721 is a wasteful number, since it uses less digits than its factorization.

420902721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46766975 (or 46766972 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 27.

The square root of 420902721 is about 20515.9138475477. The cubic root of 420902721 is about 749.4233914771.

The spelling of 420902721 in words is "four hundred twenty million, nine hundred two thousand, seven hundred twenty-one".