690142721 has 4 divisors (see below), whose sum is σ = 691584000. Its totient is φ = 688701444.

The previous prime is 690142711. The next prime is 690142729. The reversal of 690142721 is 127241096.

It is a happy number.

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 690142721 - 2²⁶ = 623033857 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (690142729) 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, 719921 + ... + 720878.

It is an arithmetic number, because the mean of its divisors is an integer number (172896000).

Almost surely, 2^690142721 is an apocalyptic number.

It is an amenable number.

690142721 is a deficient number, since it is larger than the sum of its proper divisors (1441279).

690142721 is a wasteful number, since it uses less digits than its factorization.

690142721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1441278.

The product of its (nonzero) digits is 6048, while the sum is 32.

The square root of 690142721 is about 26270.5675804692. The cubic root of 690142721 is about 883.7165137454.

The spelling of 690142721 in words is "six hundred ninety million, one hundred forty-two thousand, seven hundred twenty-one".